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The COVID-19 pandemic is an ongoing global
pandemic A pandemic (from , , "all" and , , "local people" the 'crowd') is an of an that has spread across a large region, for instance multiple or worldwide, affecting a substantial number of individuals. A widespread disease with a stable number o ...

pandemic
of
coronavirus disease 2019 Coronavirus disease 2019 (COVID-19) is a contagious disease A contagious disease (or communicable disease) is a disease A disease is a particular abnormal condition that negatively affects the structure or function of all or p ...
(COVID-19) caused by
severe acute respiratory syndrome coronavirus 2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is the coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a Novel coro ...
(SARS-CoV-2). The
novel virus A novel virus is a virus that has not previously been recorded. It can be a virus that is isolated from its natural reservoir or isolated as the result of Zoonosis, spread to an animal or human host where the virus had not been identified before. I ...
was first identified from an outbreak in the Chinese city of
Wuhan Wuhan (, ; ; ) is the capital of Hubei Province Hubei (; Postal romanization, alternately Hupeh) is a landlocked provinces of China, province of the China, People's Republic of China, and is part of the Central China region. The name of t ...

Wuhan
in December 2019, and attempts to contain it there failed, allowing it to spread across the globe. The
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
(WHO) declared a
Public Health Emergency of International Concern A Public Health Emergency of International Concern (PHEIC) is a formal declaration by the World Health Organization (WHO) of "an extraordinary event which is determined to constitute a public health risk to other States through the international ...
on 30 January 2020 and a pandemic on 11 March 2020. As of , the pandemic had caused more than cases and deaths, making it one of the deadliest in history. COVID-19 symptoms range from
none None may refer to: * Zero, the mathematical concept of the quantity "none" * Empty set, the mathematical concept of the collection of things represented by "none" *''none'', an indefinite pronoun An indefinite pronoun is a pronoun In linguistics ...
to deadly. Severe illness is more likely in elderly patients and those with certain underlying medical conditions. COVID-19 is
airborne Airborne or Airborn may refer to: Arts, entertainment, and media Films * Airborne (1962 film), ''Airborne'' (1962 film), a 1962 American film directed by James Landis * Airborne (1993 film), ''Airborne'' (1993 film), a comedy–drama film * Air ...
, spread via air contaminated by microscopic
virions A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous syst ...

virions
(viral particles). The risk of infection is highest among people in close proximity, but can occur over longer distances, particularly indoors in poorly ventilated areas. Transmission rarely occurs via contaminated surfaces or fluids. Infected persons are typically contagious for 10 days, often beginning before or without symptoms. Mutations produced many strains (variants) with varying degrees of infectivity and virulence.
COVID-19 vaccine File:COVID-19 vaccine map.svg, upright=1.2, Map of countries by approval status A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus ...
s have been approved and widely
distributedDistribution may refer to: Mathematics *Distribution (mathematics) Distributions, also known as Schwartz distributions or generalized functions, are objects that generalize the classical notion of functions in mathematical analysis. Distr ...
in various countries since December 2020. Other recommended preventive measures include
social distancing In public health, social distancing, also called physical distancing, (NB. Regula Venske is president of the .) is a set of or measures intended to of a by maintaining a physical distance between people and reducing the number of times pe ...
,
masking
masking
, improving
ventilation Ventilation may refer to: * Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation ** Mechanical ventilation, in medicine, using artificial methods to assist breathing *** Ventilator, a mac ...
and air filtration, and quarantining those who have been exposed or are symptomatic. Treatments include
monoclonal antibodies A monoclonal antibody (mAb or moAb) is an antibody An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and Viral ...

monoclonal antibodies
and symptom control. Governmental interventions include travel restrictions, lockdowns, business restrictions and closures, workplace hazard controls, quarantines, testing systems, and
tracing contacts
tracing contacts
of the infected. The pandemic triggered severe
social Social organisms, including humans, live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary/involuntary. Etymology The word "Social" derives fr ...
and economic disruption around the world, including the largest global recession since the
Great Depression The Great Depression was a severe worldwide that took place mostly during the 1930s, beginning . The timing of the Great Depression varied around the world; in most countries, it started in 1929 and lasted until the late 1930s. It was the l ...
. Widespread supply shortages, including food shortages, were caused by
supply chain In , a supply chain is a system of organizations, people, activities, information, and resources involved in supplying a or to a consumer. Supply chain activities involve the transformation of s, s, and components into a finished product and de ...

supply chain
disruption and
panic buying Panic buying (alternatively hyphenated as panic-buying; also known as panic purchasing) occurs when consumer A consumer is a person or a group who intends to order, orders, or uses purchased goods, products, or Service (economics), services pri ...
. The resultant near-global lockdowns saw an unprecedented pollution decrease.
Educational institutions An educational institution is a place where people of different ages gain an education, including preschools, childcare, primary-elementary schools, secondary-high schools, and universities. They provide a large variety of learning environments and ...
and public areas were partially or fully closed in many jurisdictions, and many events were cancelled or postponed.
Misinformation Misinformation is false, inaccurate, or misleading information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of its characteris ...
circulated through
social media Social media are interactive technologies that facilitate the creation Creation may refer to: Religion * Creation ''ex nihilo'', the concept that matter was created by God out of nothing * Creation myth A creation myth (or cosmogonic myth) ...
and
mass media Mass media refers to a diverse array of media Media may refer to: Physical means Communication * Media (communication), tools used to deliver information or data ** Advertising media, various media, content, buying and placement fo ...
, and political tensions intensified. The pandemic raised issues of racial and geographic discrimination,
health equity Health equity arises from access to the , specifically from wealth, power and prestige. Individuals who have consistently been deprived of these three determinants are significantly disadvantaged from health inequities, and face worse health outc ...
, and
the balance ''The Balance'' is the third studio album by Welsh band Catfish and the Bottlemen. It was released on 26 April 2019 through Island Records Island Records is a British-Jamaican record label owned by Universal Music Group. It was founded in 195 ...
between public health imperatives and individual rights.


Etymology

The pandemic is known by several names. It may be referred to as the "coronavirus pandemic", despite the existence of other
human coronaviruses Coronaviruses are a group of related RNA viruses that cause diseases in mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia (), and characterized by t ...
that have caused epidemics and outbreaks (e.g.
SARS Severe acute respiratory syndrome (SARS) is a viral respiratory disease Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange Gas exchange is the physical process by which ga ...
). During the initial outbreak in
Wuhan Wuhan (, ; ; ) is the capital of Hubei Province Hubei (; Postal romanization, alternately Hupeh) is a landlocked provinces of China, province of the China, People's Republic of China, and is part of the Central China region. The name of t ...

Wuhan
, the virus and disease were commonly referred to as "coronavirus", "Wuhan coronavirus", "the coronavirus outbreak" and the "Wuhan coronavirus outbreak" with the disease sometimes called "Wuhan pneumonia". In January 2020, the WHO recommended 2019-nCoV and 2019-nCoV acute respiratory disease as interim names for the virus and disease per 2015 international guidelines against using geographical locations (e.g. Wuhan, China), animal species, or groups of people in disease and virus names in part to prevent
social stigma Social stigma is the disapproval of, or discrimination against, an individual or group based on perceivable social characteristics that serve to distinguish them from other members of a society. Social stigmas are commonly related to culture, ge ...
. WHO finalized the official names COVID-19 and SARS-CoV-2 on 11 February 2020.
Tedros Adhanom Tedros Adhanom Ghebreyesus ( Ge'ez: ቴዎድሮስ አድሓኖም ገብረኢየሱስ, , , , , , , ; born 3 March 1965) is an Ethiopian biologist, public health researcher, and official who has served since 2017 as Director-General of the ...
explained: COfor ''corona'', VIfor ''virus'', Dfor ''disease'' and 19 for when the outbreak was first identified (31 December 2019). WHO additionally uses "the COVID-19 virus" and "the virus responsible for COVID-19" in public communications. WHO names variants of concern and variants of interest using
Greek letters#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 million as of ...

Greek letters
. The initial practice of naming them according to where the variants were identified (e.g. Delta began as the "Indian variant") is no longer common. A more systematic naming scheme reflects the variant's PANGO lineage (e.g., Omicron's lineage is B.1.1.529) and is used for other variants.


Epidemiology


Background

SARS-CoV-2 is a newly discovered virus that is closely related to bat coronaviruses,
pangolin Pangolins, sometimes known as scaly anteaters, are mammals Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in t ...

pangolin
coronaviruses, and
SARS-CoV Severe acute respiratory syndrome coronavirus (SARS-CoV or SARS-CoV-1) is a strain (biology), strain of virus that causes severe acute respiratory syndrome (SARS). It is an Viral envelope, enveloped, Sense (molecular biology), positive-sense, RN ...
. The first known
outbreak In epidemiology, an outbreak is a sudden increase in occurrences of a disease in a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Four linked cases of a rare inf ...
started in
Wuhan Wuhan (, ; ; ) is the capital of Hubei Province Hubei (; Postal romanization, alternately Hupeh) is a landlocked provinces of China, province of the China, People's Republic of China, and is part of the Central China region. The name of t ...

Wuhan
, Hubei, China, in November 2019. Many early cases were linked to people who had visited the there, but it is possible that human-to-human transmission began earlier. The scientific consensus is that the virus is most likely of
zoonotic A zoonosis (plural zoonoses, or zoonotic diseases) is an infectious disease caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has Cross-species transmission, jumped from an animal (usually a vertebra ...
origin, from bats or another closely-related mammal. Despite this, the subject has generated extensive speculation about alternative origins. The origin controversy heightened geopolitical divisions, notably between the United States and China. The earliest known infected person fell ill on 1December 2019. That individual did not have a connection with the later
wet market A wet market (also called a public market or a traditional market) is a marketplace A market, or marketplace, is a location where people regularly go to gather for the purchase and sale of provisions, livestock, and other goods. In di ...
cluster. However, an earlier case may have occurred on 17 November. Two-thirds of the initial case cluster were linked with the market.
Molecular clock The molecular clock is a figurative term for a technique that uses the mutation rate In genetics Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) Thou ...
analysis suggests that the
index case #redirectIndex case#redirectIndex case The index case or patient zero is the first documented patient in a Epidemic, disease epidemic within a population, or the first documented patient included in an epidemiology, epidemiological study. It can a ...
is likely to have been infected between mid-October and mid-November 2019.


Cases

Official "case" counts refer to the number of people who have been tested for COVID-19 and whose test has been confirmed positive according to official protocols whether or not they experienced symptomatic disease. Many countries, early on, had official policies to not test those with only mild symptoms. Multiple studies claimed that total infections are considerably greater than reported cases. The strongest risk factors for severe illness are obesity,
complications of diabetes Complications of diabetes mellitus include problems that develop rapidly (acute) or over time (chronic) and may affect many organ systems. The complications of diabetes can dramatically impair quality of life and cause long-lasting disability. Over ...
, anxiety disorders, and the total number of conditions. On 9 April 2020, preliminary results found that in Gangelt, the centre of a major infection cluster in Germany, 15 percent of a population sample tested positive for
antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and Viral disease, viruses. The antibody recognizes a unique mo ...

antibodies
. Screening for COVID-19 in pregnant women in New York City, and
blood donor A blood donation occurs when a person voluntarily has blood Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrient A nutrient is a substance used by an organism to survive, grow, and reprod ...
s in the Netherlands, found rates of positive antibody tests that indicated more infections than reported.
Seroprevalence Seroprevalence is the number of persons in a population who test positive for a specific disease based on serology Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identificat ...
-based estimates are conservative as some studies show that persons with mild symptoms do not have detectable antibodies. An analysis in early 2020 of cases in China by age indicated that a relatively low proportion of cases occurred in individuals under 20. It was not clear whether this was because young people were less likely to be infected, or less likely to develop symptoms and be tested. A retrospective
cohort study A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing ...
in China found that
children Biologically, a child (plural children) is a being between the stages of and , or between the of and puberty. The legal definition of ''child'' generally refers to a , otherwise known as a person younger than the . Children generally have ...
and adults were just as likely to be infected. Initial estimates of the
basic reproduction number In epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants In mathematics, the determinant is a Scalar (mathematics), scalar value that is a function (mathematics), functio ...
(R0) for COVID-19 in January were between 1.4 and 2.5, but a subsequent analysis claimed that it may be about 5.7 (with a 95 percent
confidence interval In statistics Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with ...

confidence interval
of 3.8 to 8.9). In December 2021, the number of cases continued to climb due to several factors including new COVID-19 variants. As of 28December there were 282,790,822 confirmed infected individuals worldwide. File:Covid-19 new cases in top 5 countries and the world.png, Semi-log plot of weekly new cases of COVID-19 in the world and the current top six countries (mean with deaths) File:Covid-19 total cases per 100 000 population from selected countries.png, Total COVID-19 cases per 100,000 people from selected countries File:COVID-19 Active Cases per 100 000 population.png, Active COVID-19 cases per 100,000 people from selected countries


Deaths

As of , more than deaths had been attributed to COVID-19. The first confirmed death was in Wuhan on 9 January 2020. These numbers vary by region and over time, influenced by testing volume, healthcare system quality, treatment options, government response, time since the initial outbreak, and population characteristics, such as age, sex, and overall health. Multiple measures are used to quantify mortality. Official death counts typically include people who died after testing positive. Such counts exclude deaths without a test. Conversely, deaths of people who died from underlying conditions following a positive test may be included. Countries such as Belgium include deaths from suspected cases, including those without a test, thereby increasing counts. Official death counts have been claimed to underreport the actual death toll, because excess mortality (the number of deaths in a period compared to a long-term average) data show an increase in deaths that is not explained by COVID-19 deaths alone. Using such data, estimates of the true number of deaths from COVID-19 worldwide have included a range from 9.5 to 18.6 million by ''
The Economist ''The Economist'' is an international weekly newspaper A weekly newspaper is a general-news or current affairsCurrent affairs may refer to: Media * Current Affairs (magazine), ''Current Affairs'' (magazine), a bimonthly magazine of cult ...
'', as well as over 10.3 million by the
Institute for Health Metrics and Evaluation The Institute for Health Metrics and Evaluation (IHME) is a research institute working in the area of global health statistics and impact evaluation at the University of Washington in Seattle. The Institute is headed by Christopher J.L. Murray, ...
. Such deaths include deaths due to healthcare capacity constraints and priorities, as well as reluctance to seek care (to avoid possible infection). The time between symptom onset and death ranges from6 to 41 days, typically about 14 days. Mortality rates increase as a function of age. People at the greatest mortality risk are the elderly and those with underlying conditions.
File:Covid-19 daily deaths in top 5 countries and the world.png, Semi-log plot of weekly deaths due to COVID-19 in the world and top six current countries (mean with cases) File:COVID-19 deaths per 100,000 population.png, COVID-19 deaths per 100 000 population from selected countries


Infection fatality ratio (IFR)

The infection fatality ratio (IFR) is the cumulative number of deaths attributed to the disease divided by the cumulative number of infected individuals (including asymptomatic and undiagnosed infections). It is expressed in percentage points (not as a decimal). Other studies refer to this metric as the 'infection fatality risk'. In November 2020, a review article in ''Nature'' reported estimates of population-weighted IFRs for various countries, excluding deaths in elderly care facilities, and found a median range of 0.24% to 1.49%. IFRs rise as a function of age (from 0.002% at age 10 and 0.01% at age 25, to 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85). These rates vary by a factor of ~10,000 across the age groups. For comparison the IFR for middle-aged adults is two orders of magnitude more likely than the annualised risk of a fatal automobile accident and far more dangerous than seasonal influenza. In December 2020, a systematic review and meta-analysis estimated that population-weighted IFR was 0.5% to 1% in some countries (France, Netherlands, New Zealand, and Portugal), 1% to 2% in other countries (Australia, England, Lithuania, and Spain), and about 2.5% in Italy. This study reported that most of the differences reflected corresponding differences in the population's age structure and the age-specific pattern of infections.


Case fatality ratio (CFR)

Another metric in assessing death rate is the case fatality ratio (CFR), which is the ratio of deaths to diagnoses. This metric can be misleading because of the delay between symptom onset and death and because testing focuses on symptomatic individuals. Based on
Johns Hopkins University The Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty S ...

Johns Hopkins University
statistics, the global CFR is ( deaths for cases) as of . The number varies by region and has generally declined over time.


Disease


Signs and symptoms

Symptoms of COVID-19 are variable, ranging from mild symptoms to severe illness. Common symptoms include
headache Headache is the symptom of pain Pain is a distressing feeling often caused by intense or damaging stimuli. The defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or ...

headache
, and
taste The gustatory system or sense of taste is the sensory system The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory re ...
,
nasal congestion Nasal congestion is the blockage of nasal breathing usually due to membranes lining the nose becoming swollen from inflamed blood vessels. Background In about 85% of cases, nasal congestion leads to mouth breathing rather than nasal breathing ...
and
runny nose Rhinorrhea or rhinorrhoea is the free discharge of a thin nasal mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also origi ...
,
cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, ...
,
muscle pain Myalgia (also called muscle pain and muscle ache) is the medical term for muscle Muscle is a soft tissue found in most animals. Muscle cells contain protein Proteins are large biomolecules or macromolecules that are comprised of one or ...
,
sore throat Sore throat, also known as throat pain, is pain or irritation of the throat. Sore throat is usually caused by a viral infection or a group A streptococcal infection (GAS) bacterial infection. Other causes include pharyngitis (inflammation of the th ...
,
fever Fever, also referred to as pyrexia, is defined as having a temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on th ...

fever
,
diarrhoea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movement frame, Anatomy of the anus and rectum Defecation is the final act of digestion Digestion is the breakdown of large ins ...
, and
breathing difficulties upright=1.4, X-ray video of a female American alligator while breathing. Breathing (or ventilation) is the process of moving air File:Atmosphere gas proportions.svg, Composition of Earth's atmosphere by volume, excluding water vapor. Low ...
. People with the same infection may have different symptoms, and their symptoms may change over time. Three common clusters of symptoms have been identified: one respiratory symptom cluster with cough,
sputum Sputum is mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body and covers the surface of internal organs. It consists o ...
, shortness of breath, and fever; a musculoskeletal symptom cluster with muscle and joint pain, headache, and fatigue; a cluster of digestive symptoms with abdominal pain, vomiting, and diarrhoea. In people without prior ear, nose, and throat disorders, loss of taste combined with loss of smell is associated with
COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease A contagious disease is a disease A disease is a particular abnormal condition that negatively affects the structure A structure is an arrangement and organization o ...

COVID-19
and is reported in as many as 88% of cases.


Transmission

The disease is mainly transmitted via the respiratory route when people inhale droplets and small airborne particles (that form an
aerosol An aerosol (abbreviation of "aero-solution") is a suspension Suspension or suspended may refer to: Science and engineering * Suspension (topology), in mathematics * Suspension (dynamical systems), in mathematics * Suspension of a ring, in math ...

aerosol
) that infected people exhale as they breathe, talk, cough, sneeze, or sing. Infected people are more likely to transmit COVID-19 when they are physically close. However, infection can occur over longer distances, particularly indoors.


Cause

SARS‑CoV‑2 belongs to the broad family of viruses known as
coronavirus Coronaviruses are a group of related Orthornavirae, RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some ca ...

coronavirus
es. It is a positive-sense single-stranded RNA (+ssRNA) virus, with a single linear RNA segment. Coronaviruses infect humans, other mammals, including livestock and companion animals, and avian species. Human coronaviruses are capable of causing illnesses ranging from the
common cold The common cold, also known simply as a cold, is a viral infectious disease An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction of host (b ...
to more severe diseases such as
Middle East respiratory syndrome Mers may refer to: * MERS Mers may refer to: * MERS, Middle East respiratory syndrome ** Middle East respiratory syndrome–related coronavirus (MERS-CoV), the virus that causes MERS * El Mers, a town in Morocco * Mer (community) or Maher communi ...
(MERS, fatality rate ~34%). SARS-CoV-2 is the seventh known coronavirus to infect people, after , NL63, OC43, HKU1, , and the original
SARS-CoV Severe acute respiratory syndrome coronavirus (SARS-CoV or SARS-CoV-1) is a strain (biology), strain of virus that causes severe acute respiratory syndrome (SARS). It is an Viral envelope, enveloped, Sense (molecular biology), positive-sense, RN ...
.


Diagnosis

The standard methods of testing for presence of SARS-CoV-2 are
nucleic acid test A nucleic acid test (NAT) is a technique used to detect a particular nucleic acid sequence and thus usually to detect and identify a particular species or subspecies of organism, often a virus or bacterium that acts as a pathogen in blood, Tissue ...
s, which detects the presence of viral RNA fragments. As these tests detect RNA but not infectious virus, its "ability to determine duration of infectivity of patients is limited." The test is typically done on respiratory samples obtained by a nasopharyngeal swab; however, a nasal swab or sputum sample may also be used. The WHO has published several testing protocols for the disease.


Prevention

Preventive measures to reduce the chances of infection include getting vaccinated, staying at home, wearing a mask in public, avoiding crowded places, keeping distance from others, ventilating indoor spaces, managing potential exposure durations, washing hands with soap and water often and for at least twenty seconds, practising good respiratory hygiene, and avoiding touching the eyes, nose, or mouth with unwashed hands. Those diagnosed with COVID-19 or who believe they may be infected are advised by the CDC to stay home except to get medical care, call ahead before visiting a healthcare provider, wear a face mask before entering the healthcare provider's office and when in any room or vehicle with another person, cover coughs and sneezes with a tissue, regularly wash hands with soap and water and avoid sharing personal household items.


Vaccines

A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against
severe acute respiratory syndrome coronavirus 2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is the coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a Novel coro ...
(SARS‑CoV‑2), the virus that causes coronavirus disease 2019 (COVID‑19). Prior to the COVID‑19 pandemic, an established body of knowledge existed about the structure and function of
coronavirus Coronaviruses are a group of related Orthornavirae, RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some ca ...

coronavirus
es causing diseases like severe acute respiratory syndrome (SARS) and
Middle East respiratory syndrome Mers may refer to: * MERS Mers may refer to: * MERS, Middle East respiratory syndrome ** Middle East respiratory syndrome–related coronavirus (MERS-CoV), the virus that causes MERS * El Mers, a town in Morocco * Mer (community) or Maher communi ...
(MERS). This knowledge accelerated the development of various vaccine platforms during early 2020. The initial focus of SARS-CoV-2 vaccines was on preventing symptomatic, often severe illness. On 10 January 2020, the SARS-CoV-2 DNA sequencing, genetic sequence data was shared through GISAID, and by 19 March, the global pharmaceutical industry announced a major commitment to address COVID‑19. The COVID‑19 vaccines are widely credited for their role in reducing the severity and death caused by COVID‑19. As of late-December 2021, more than 4.49 billion people had received one or more doses (8+ billion in total) in over 197 countries. The Oxford-AstraZeneca vaccine was the most widely used.


Treatment

For the first two years of the pandemic no specific, effective treatment or cure was available. In 2021, the European Medicines Agency's (EMA) Committee for Medicinal Products for Human Use (CHMP) approved the oral antiviral Protease inhibitor (pharmacology), protease inhibitor, Paxlovid (nirmatrelvir plus AIDS drug ritonavir), to treat adult patients. FDA later gave it an EUA. Most cases of COVID-19 are mild. In these, supportive care includes medication such as paracetamol or NSAIDs to relieve symptoms (fever, body aches, cough), adequate intake of oral fluids and rest. Good personal hygiene and a healthy diet are also recommended. Supportive care includes treatment to Symptomatic treatment, relieve symptoms, Fluid replacement, fluid therapy, oxygen support and prone positioning, and medications or devices to support other affected vital organs. More severe cases may need treatment in hospital. In those with low oxygen levels, use of the glucocorticoid dexamethasone is recommended, to reduce mortality. Noninvasive ventilation and, ultimately, admission to an intensive care unit for mechanical ventilation may be required to support breathing. Extracorporeal membrane oxygenation (ECMO) has been used to address the issue of respiratory failure. Existing drugs such as hydroxychloroquine, lopinavir/ritonavir, ivermectin and so-called early treatment are not recommended by US or European health authorities./ Two monoclonal antibody-based therapies are available for early use in high-risk cases. The antiviral remdesivir is available in the US, Canada, Australia, and several other countries, with varying restrictions; however, it is not recommended for use with mechanical ventilation, and is discouraged altogether by the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
(WHO), due to limited evidence of its efficacy.


Variants

Several variants have been named by WHO and labelled as a variant of concern (VoC) or a variant of interest (VoI). They share the more infectious D614G mutation: Delta dominated and then eliminated earlier VoC from most jurisdictions. Omicron's immune escape ability may allow it to spread via breakthrough infections, which in turn may allow it to coexist with Delta, which more often infects the unvaccinated.


Prognosis

The severity of COVID-19 varies. The disease may take a mild course with few or no symptoms, resembling other common upper respiratory diseases such as the
common cold The common cold, also known simply as a cold, is a viral infectious disease An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction of host (b ...
. In 3–4% of cases (7.4% for those over age 65) symptoms are severe enough to cause hospitalization. Mild cases typically recover within two weeks, while those with severe or critical diseases may take three to six weeks to recover. Among those who have died, the time from symptom onset to death has ranged from two to eight weeks. Prolonged prothrombin time and elevated C-reactive protein levels on admission to the hospital are associated with severe course of COVID-19 and with a transfer to ICU.


Strategies

Many countries attempted to slow or stop the spread of COVID-19 by recommending, mandating or prohibiting behaviour changes, while others relied primarily on providing information. Measures ranged from public advisories to stringent lockdowns. Outbreak control strategies are divided into containment and mitigation. These can be pursued sequentially or simultaneously.


Containment

Containment is undertaken to stop an outbreak from spreading into the general population. Infected individuals are isolated while they are infectious. The people they have interacted with are contacted and isolated for long enough to ensure that they are either not infected or no longer contagious. Successful containment or suppression reduces Rt to less than 1. Screening is the starting point for containment. Screening is done by checking for symptoms to identify infected individuals, who can then be isolated or offered treatment.


Mitigation

Should containment fail, efforts focus on mitigation: measures taken to slow the spread and limit its effects on the healthcare system and society. Successful mitigation delays and decreases the epidemic peak, known as "flattening the epidemic curve". This decreases the risk of overwhelming health services and provides more time for developing vaccines and treatments. Individual behaviour changed in many jurisdictions. Many people worked from home instead of at their traditional workplaces.


Non-pharmaceutical interventions

Non-pharmaceutical interventions that may reduce spread include personal actions such as Hand washing, hand hygiene, wearing Face masks during the COVID-19 pandemic, face masks, and self-quarantine; community measures aimed at reducing interpersonal contacts such as closing workplaces and schools and cancelling large gatherings; community engagement to encourage acceptance and participation in such interventions; as well as environmental measures such as surface cleaning. Many such measures were criticised as hygiene theatre.


Other measures

More drastic actions, such as quarantining entire populations and strict travel bans have been attempted in various jurisdictions. China and Australia's lockdowns have been the most strict. New Zealand implemented the most severe travel restrictions. South Korea introduced mass screening and localised quarantines, and issued alerts on the movements of infected individuals. Singapore provided financial support, quarantined, and imposed large fines for those who broke quarantine.


Contact tracing

Contact tracing attempts to identify recent contacts of newly infected individuals, and to screen them for infection; the traditional approach is to request a list of contacts from infectees, and then telephone or visit the contacts. Another approach is to collect location data from mobile devices to identify those who have come in significant contact with infectees, which prompted privacy concerns. On 10 April 2020, Google and Apple Inc., Apple announced an initiative for privacy-preserving contact tracing. In Europe and in the US, Palantir Technologies initially provided COVID-19 tracking services.


Health care

WHO described increasing capacity and adapting healthcare as a fundamental mitigation. The ECDC and WHO's European regional office issued guidelines for hospitals and primary health care, primary healthcare services for shifting resources at multiple levels, including focusing laboratory services towards testing, cancelling elective procedures, separating and isolating patients, and increasing Intensive care unit, intensive care capabilities by training personnel and increasing ventilators and beds. The pandemic drove widespread adoption of telehealth.


Improvised manufacturing

Due to capacity
supply chain In , a supply chain is a system of organizations, people, activities, information, and resources involved in supplying a or to a consumer. Supply chain activities involve the transformation of s, s, and components into a finished product and de ...

supply chain
s limitations, some manufacturers began 3D printing material such as nasal swabs and ventilator parts. In one example, an Italian startup received legal threats due to alleged patent infringement after reverse-engineering and printing one hundred requested ventilator valves overnight. On 23 April 2020, NASA reported building, in 37 days, a ventilator which is undergoing further testing. Individuals and groups of Maker culture, makers created and shared open source designs, and manufacturing devices using locally sourced materials, sewing, and 3D printing. Millions of face shields, protective gowns, and masks were made. Other ad hoc medical supplies included shoe covers, surgical caps, powered air-purifying respirators, and hand sanitizer. Novel devices were created such as ear savers, non-invasive ventilation helmets, and ventilator splitters.


Herd immunity

In July 2021, several experts expressed concern that achieving herd immunity may not be possible because Delta can transmit among vaccinated individuals. CDC published data showing that vaccinated people could transmit Delta, something officials believed was less likely with other variants. Consequently, WHO and CDC encouraged vaccinated people to continue with non-pharmaceutical interventions.


History


2019

The
outbreak In epidemiology, an outbreak is a sudden increase in occurrences of a disease in a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Four linked cases of a rare inf ...
was discovered in Wuhan in November 2019. It is possible that human-to-human transmission was happening before the discovery. Based on a retrospective analysis starting from December 2019, the number of cases in Hubei gradually increased, reaching 60 by 20 December and at least 266 by 31 December. A pneumonia cluster was observed on 26 December and treated by Doctor Zhang Jixian. He informed the Wuhan Jianghan CDC on 27 December. Vision Medicals reported the discovery of a novel coronavirus to the Chinese Center for Disease Control and Prevention, China CDC (CCDC) on 28 December. On 30 December, a test report from CapitalBio Medlab addressed to Wuhan Central Hospital reported an erroneous positive result for SARS, causing doctors there to alert authorities. Eight of those doctors, including Li Wenliang (who was also punished on 3January), were later admonished by the police for spreading false rumours; and Dr. Ai Fen was reprimanded. That evening, Wuhan Municipal Health Commission (WMHC) issued a notice about "the treatment of pneumonia of unknown cause". The next day, WMHC made the announcement public, confirming 27 cases—enough to trigger an investigation. On 31 December, the WHO office in China was informed of cases of the pneumonia cases and immediately launched an investigation. Official Chinese sources claimed that the early cases were mostly linked to the Huanan Seafood Wholesale Market, which also sold live animals. However, in May 2020, CCDC director George F. Gao, George Gao indicated the market was not the origin (animal samples had tested negative).


2020

On 11 January, WHO was notified by the Chinese National Health Commission that the outbreak was associated with exposures in the market, and that China had identified a new type of coronavirus, which it isolated on 7 January. Initially, the number of cases doubled approximately every seven and a half days. In early and mid-January, the virus spread to other Provinces of China, Chinese provinces, helped by the Chunyun, Chinese New Year migration. Wuhan was a transport hub and major rail interchange. On 10 January, the virus' genome was shared through GISAID. A retrospective study published in March found that 6,174 people had reported symptoms by 20 January. A 24 January report indicated human transmission, recommended personal protective equipment for health workers, and advocated testing, given the outbreak's "pandemic potential". On 31 January the first published modelling study warned of inevitable "independent self-sustaining outbreaks in major cities globally" and called for "large-scale public health interventions." On 30 January, 7,818 infections had been confirmed, leading WHO to declare the outbreak a
Public Health Emergency of International Concern A Public Health Emergency of International Concern (PHEIC) is a formal declaration by the World Health Organization (WHO) of "an extraordinary event which is determined to constitute a public health risk to other States through the international ...
(PHEIC). On 11 March, WHO elevated it to a pandemic. By 31 January, Italy had its first confirmed infections, in two tourists from China. On 19 March, Italy overtook China as the country with the most reported deaths. By 26 March, the United States had overtaken China and Italy as the country with the highest number of confirmed infections. Genomic analysis indicated that the majority of COVID-19 pandemic in New York (state), New York's confirmed infections came from Europe, rather than directly from Asia. Testing of prior samples revealed a person who was infected in France on 27 December 2019 and a person in the United States who died from the disease on 6February. In April Russia sent a cargo plane with medical aid to the United States. In October, WHO reported that one in ten people around the world may have been infected, or 780 million people, while only 35 million infections had been confirmed. On 9 November, Pfizer released trial results for a candidate vaccine, showing that 90% effectiveness against severe infection. That day, Novavax entered an Food and Drug Administration, FDA Fast Track application for their vaccine. On 14 December, Public Health England reported that a variant had been discovered in the UK's southeast, predominantly in Kent. The variant, later named Variant of Concern 202012/01, Alpha, showed changes to the coronavirus spike protein, spike protein that could be more infectious. As of 13 December, 1,108 infections had been confirmed. On 4 February 2020, US Secretary of Health and Human Services Alex Azar waived liability for vaccine manufacturers.


2021

On 2 January, the SARS-CoV-2 Alpha variant, Alpha variant, first discovered in the UK, had been identified in 33 countries. On 6 January, the Lineage P.1, Gamma variant was first identified in Japanese travellers returning from Brazil. On 29 January, it was reported that the Novavax vaccine was 49% effective against the SARS-CoV-2 Beta variant, Beta variant in a clinical trial in South Africa. The CoronaVac vaccine was reported to be 50.4% effective in a Brazil clinical trial. On 12 March, several countries stopped using the Oxford-AstraZeneca COVID-19 vaccine due to blood clotting problems, specifically cerebral venous sinus thrombosis (CVST). On 20 March, the WHO and European Medicines Agency found no link to thrombus, leading several countries to resume the vaccine. In March WHO reported that an animal host was the most likely origin, without ruling out other possibilities. The SARS-CoV-2 Delta variant, Delta variant was first identified in India. In mid-April, the variant was first detected in the UK and two months later it had metastasized into a third wave there, forcing the government to delay reopening that was originally scheduled for June. On 10 November, Germany advised against the Moderna vaccine for people under 30. On 24 November the Omicron variant was detected in South Africa; a few days later the World Health Organization declared it a VoC (variant of concern). The new variant is more infectious than the Delta variant.


National responses

National reactions ranged from strict lockdowns to public education. WHO recommended that curfews and lockdowns should be short-term measures to reorganise, regroup, rebalance resources, and protect the health care system. As of 26 March 2020, 1.7 billion people worldwide were under some form of lockdown. This increased to 3.9 billion people by the first week of April—more than half the World population, world's population.


Asia

As of the end of 2021, Asia's peak had come at the same time and at the same level as the world as a whole, in May 2021. However, cumulatively they had experienced only half the world average. China opted for containment, inflicting strict lockdowns to eliminate spread.


China

As of 14 July 2020, 83,545 cases had been confirmed in China, along with 4,634 deaths and 78,509 recoveries. In November 2020 some 1 million people had been vaccinated, according to China's state council. The vaccines included the Sinopharm BIBP COVID-19 vaccine, BIBP, Sinopharm WIBP COVID-19 vaccine, WIBP, and CoronaVac. Multiple sources cast doubt upon the accuracy of China's official numbers, with some suggesting intentional data suppression. It was reported on 11 December 2021 that China had vaccinated 1.162 billion of its citizens, or 82.5% of the total population of the country against COVID-19.


India

The first case in India was reported on 30 January 2020. India ordered a nationwide lockdown starting 24 March 2020, with a phased unlock beginning 1 June 2020. Six cities accounted for around half of reported cases—COVID-19 pandemic in Maharashtra, Mumbai, COVID-19 pandemic in Delhi, Delhi, COVID-19 pandemic in Gujarat, Ahmedabad, COVID-19 pandemic in Tamil Nadu, Chennai, COVID-19 pandemic in Maharashtra, Pune and COVID-19 pandemic in West Bengal, Kolkata. A second wave hit India in April 2021, straining healthcare services. On 21, October it was reported that the country had surpassed 1 billion vaccinations.


Iran

Iran reported its first confirmed cases on 19 February 2020 in Qom. Early measures included the cancellation of concerts and other cultural events, Friday prayers, and education shutdowns. Iran became a centre of the pandemic in February 2020. More than ten countries had traced their outbreaks to Iran by 28 February, indicating a more severe outbreak than the 388 reported cases. The Islamic Consultative Assembly, Iranian Parliament closed, after 23 of its 290 members tested positive on 3March 2020. At least twelve sitting or former Iranian politicians and government officials had died by 17 March 2020. By August 2021, the pandemic's fifth wave peaked, with more than 400 deaths in 1 day.


Japan

In COVID-19 pandemic in Japan, Japan, the pandemic was believed to have damaged mental health. According to the report by the country's National Police Agency (Japan), National Police Agency, suicides increased to 2,153 in October 2020. Experts stated that the pandemic had worsened mental health issues due to lockdowns and isolation from family members, among other issues.


South Korea

COVID-19 was confirmed in South Korea on 20 January 2020. Military bases were quarantined after tests showed three infected soldiers. South Korea introduced what was then considered the world's largest and best-organised screening programme, isolating infected people, and tracing and quarantining contacts. Screening methods included mandatory self-reporting by new international arrivals through mobile application, combined with drive-through testing, and increasing testing capability to 20,000 people/day. Despite some early criticisms, South Korea's programme was considered a success in controlling the outbreak without quarantining entire cities.


Europe

The global COVID-19 pandemic arrived in Europe with its first confirmed case in Bordeaux, COVID-19 pandemic in France, France, on 24 January 2020, and subsequently spread widely across the continent. By 17 March 2020, every country in Europe had confirmed a case, and all have reported at least one death, with the exception of COVID-19 pandemic in Vatican City, Vatican City. COVID-19 pandemic in Italy, Italy was the first European nation to experience a major outbreak in early 2020, becoming the first country worldwide to introduce a national COVID-19 lockdowns in Italy, lockdown. By 13 March 2020, the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
(WHO) declared Europe the epicentre of the pandemic and it remained so until the WHO announced it has been overtaken by COVID-19 pandemic in South America, South America on 22 May. By 18 March 2020, more than 250 million people were in Stay-at-home order, lockdown in Europe. Despite deployment of COVID-19 vaccines, Europe became the pandemic's epicentre once again in late 2021. On 21 August, it was reported the COVID-19 cases were climbing among younger individuals across Europe. On 21 November, it was reported by the Voice of America that Europe is the worst hit area by COVID-19, with numbers exceeding 15 million cases. On 22 November, the WHO indicated that a new surge of the virus in Europe had caused Austria to implement another lockdown, while other countries in the region such as Germany are contemplating a lockdown, due to rising cases, as well.


France

The earliest discovered infection came from an old sample collected on 27 December 2019. A superspreader event in the outbreak was the annual assembly of the Christian Open Door Church between 17 and 24 February. It was attended by about 2,500 people, at least half of whom were believed to have contracted the virus. On 13 March, Prime Minister Édouard Philippe ordered the closure of "non-essential" public places, and on 16 March, President Emmanuel Macron announced mandatory home confinement.


Italy

The Italian outbreak began on 31 January 2020, when two Chinese tourists tested positive for SARS-CoV-2 in Rome. Cases began to rise sharply, which prompted the government to suspend flights to and from China and declare a state of emergency. On 22 February 2020, the Council of Ministers announced a new decree-law to contain the outbreak, including quarantining more than 50,000 people in northern Italy. On 4 March the Italian government ordered schools and universities closed as Italy reached a hundred deaths. Sport was suspended completely for at least one month. On 11 March Conte stopped nearly all commercial activity except supermarkets and pharmacies. On 19 March Italy overtook China as the country with the most COVID-19-related deaths. On 19 April the first wave ebbed, as 7-day deaths declined to 433. On 13 October, the Italian government again issued restrictive rules to contain the second wave. On 10 November Italy surpassed 1 million confirmed infections. On 23 November, it was reported that the second wave of the virus had led some hospitals to stop accepting patients.


Spain

The virus was first confirmed to have spread to Spain on 31 January 2020, when a German tourist tested positive for SARS-CoV-2 in La Gomera, Canary Islands. Post-hoc genetic analysis has shown that at least 15 strains of the virus had been imported, and Transmission (medicine)#Definition and related terms, community transmission began by mid-February. On 29 March, it was announced that, beginning the following day, all non-essential workers were ordered to remain at home for the next 14 days. By late March, the COVID-19 pandemic in the Community of Madrid, Community of Madrid has recorded the most cases and deaths in the country. Medical professionals and those who live in retirement homes have experienced especially high infection rates. On 25 March, the official death toll in Spain surpassed COVID-19 pandemic in mainland China, that of mainland China. On 2April, 950 people died of the virus in a 24-hour period—at the time, the most by any country in a single day. On 17 May, the daily death toll announced by the Spanish government fell below 100 for the first time, and 1 June was the first day without deaths by COVID-19. The state of alarm ended on 21 June. However, the number of cases increased again in July in a number of cities including Barcelona, Zaragoza and Madrid, which led to reimposition of some restrictions but no national lockdown. As of September 2021, Spain is one of the countries with the highest percentage of its population vaccinated (76% fully vaccinated and 79% with the first dose), while also being one of the countries more in favour of vaccines against COVID-19 (nearly 94% of its population is already vaccinated or wants to be).


Sweden

Sweden differed from most other European countries in that it mostly remained open. Per the Swedish Constitution, the Public Health Agency of Sweden has autonomy that prevents political interference and the agency favoured remaining open. The Swedish strategy focused on longer-term measures, based on the assumption that after lockdown the virus would resume spreading, with the same result. By the end of June, Sweden no longer had excess mortality.


United Kingdom

Devolution in the United Kingdom meant that each of its four Countries of the United Kingdom, countries developed its own response. England's restrictions were shorter-lived than the others. The Government of the United Kingdom, UK government started enforcing social distancing and quarantine measures on 18 March. On 16 March, Prime Minister Boris Johnson advised against non-essential travel and social contact, praising Remote work, work from home and avoiding venues such as pubs, restaurants, and theatres. On 20 March, the government ordered all leisure establishments to close, and promised to prevent unemployment. On 23 March, Johnson banned gatherings and restricted non-essential travel and outdoor activity. Unlike previous measures, these restrictions were enforceable by police through fines and dispersal of gatherings. Most non-essential businesses were ordered to close. On 24 April, it was reported that a promising vaccine trial had begun in England; the government pledged more than £50 million towards research. On 16 April, it was reported that the UK would have first access to the Oxford vaccine, due to a prior contract; should the trial be successful, some 30 million doses would be available. On 2 December, the UK became the first developed country to approve the Pfizer vaccine; 800,000 doses were immediately available for use. On 9 December, MHRA stated that any individual with a significant allergic reaction to a vaccine, such as an Anaphylaxis, anaphylactoid reaction, should not take the Pfizer vaccine.


North America

The first cases of the COVID-19 pandemic of
coronavirus disease 2019 Coronavirus disease 2019 (COVID-19) is a contagious disease A contagious disease (or communicable disease) is a disease A disease is a particular abnormal condition that negatively affects the structure or function of all or p ...
in North America were reported in the COVID-19 pandemic in the United States, United States on 23 January 2020. Cases were reported in all North American countries after COVID-19 pandemic in Saint Kitts and Nevis, Saint Kitts and Nevis confirmed a case on 25 March, and in all North American territories after COVID-19 pandemic in Bonaire, Bonaire confirmed a case on 16 April.


Canada

The virus was confirmed to have reached Canada on 27 January 2020, after an individual who had returned to Toronto from
Wuhan Wuhan (, ; ; ) is the capital of Hubei Province Hubei (; Postal romanization, alternately Hupeh) is a landlocked provinces of China, province of the China, People's Republic of China, and is part of the Central China region. The name of t ...

Wuhan
, Hubei, China, tested positive. The first case of community transmission in Canada was confirmed in British Columbia on 5 March. In March 2020, as cases of community transmission were confirmed, all of Canada's provinces and territories declared states of emergency. Provinces and territories have, to varying degrees, implemented school and daycare closures, prohibitions on gatherings, closures of non-essential businesses and restrictions on entry. Canada severely restricted its border access, barring travellers from all countries with some exceptions. The federal Minister of Health invoked the Quarantine Act, 2005, ''Quarantine Act'', introduced following the 2002–2004 SARS outbreak. Near the end of summer 2021, cases began to surge across Canada, notably in the provinces of British Columbia, Alberta, Quebec and Ontario, particularly amongst the unvaccinated population. During this fourth wave of the virus, return to pandemic restrictions such as mask mandates were reinstated in provinces like British Columbia and Alberta. Due to the surge in cases largely being a "pandemic of the unvaccinated", COVID-19 Vaccine Passport, vaccine passports were adopted in all provinces and two of the territories.


United States

confirmed cases have been reported in the United States with deaths, the most of any country, and COVID-19 pandemic death rates by country, the nineteenth-highest per capita worldwide. As many infections have gone undetected, the Centers for Disease Control and Prevention (CDC) estimated that, as of May 2021, there could be a total of 120.2million infections in the United States, or more than a third of the total population. COVID-19 is the List of disasters in the United States by death toll, deadliest pandemic in U.S. history; it was the third-leading cause of death in the U.S. in 2020, behind heart disease and cancer. From 2019 to 2020, U.S. life expectancy dropped by 3years for Hispanic Americans, 2.9years for African Americans, and 1.2years for white Americans. These effects have persisted as U.S. deaths due to COVID-19 in 2021 exceeded those in 2020.
COVID-19 vaccine File:COVID-19 vaccine map.svg, upright=1.2, Map of countries by approval status A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus ...
s became available in December 2020, under emergency use, beginning the COVID-19 vaccination in the United States, national vaccination program, with the first vaccine officially approved by the Food and Drug Administration, Food and Drug Administration (FDA) on 23 August 2021. Studies have shown them to be highly protective against severe illness, hospitalization, and death. In comparison with fully vaccinated people, the CDC found that those who were not vaccinated were from 5 to nearly 30 times more likely to become either infected or hospitalized. There has nonetheless been some COVID-19 vaccine hesitancy in the United States, vaccine hesitancy for various reasons, although side effects are rare.


South America

The COVID-19 pandemic was confirmed to have reached South America on 26 February 2020 when Brazil confirmed a case in São Paulo. By 3 April, all countries and territories in South America had recorded at least one case. On 13 May 2020, it was reported that Latin America and the Caribbean had reported over 400,000 cases of COVID-19 infection with, 23,091 deaths. On 22 May 2020, citing the rapid increase of COVID-19 pandemic in Brazil, infections in Brazil, the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
WHO declared South America the epicentre of the pandemic. As of 16 July 2021, South America had recorded 34,359,631 confirmed cases and 1,047,229 deaths from COVID-19. Due to a shortage of testing and medical facilities, it is believed that the outbreak is far larger than the official numbers show.


Brazil

The virus was confirmed to have spread to Brazil on 25 February 2020, when a man from São Paulo who had traveled to Italy tested positive for the virus. The disease had spread to every Federative units of Brazil, federative unit of Brazil by 21 March. On 19 June 2020, the country reported its one millionth case and nearly 49,000 reported deaths. One estimate of Under-reporting#Disease, under-reporting was 22.62% of total reported COVID-19 mortality in 2020. As of , Brazil, with confirmed cases and deaths, has the third-highest number of confirmed cases and second-highest death toll from COVID-19 in the world, behind only COVID-19 pandemic in the United States, those of the United States and COVID-19 pandemic in India, of India.


Africa

The COVID-19 pandemic was confirmed to have spread to Africa on 14 February 2020, with the first confirmed case announced in COVID-19 pandemic in Egypt, Egypt. The first confirmed case in sub-Saharan Africa was announced in COVID-19 pandemic in Nigeria, Nigeria at the end of February 2020. Within three months, the virus had spread throughout the continent, as Lesotho, the last African sovereign state to have remained free of the virus, reported a case on 13 May 2020. By 26 May, it appeared that most African countries were experiencing community transmission, although testing capacity was limited. Most of the identified imported cases arrived from Europe and the United States rather than from China where the virus originated. In early June 2021, Africa faced a third wave of COVID infections with cases rising in 14 countries. By 4 July the continent recorded more than 251,000 new COVID cases, a 20% increase from the prior week and a 12% increase from the January peak. More than sixteen African countries, including Malawi and Senegal, recorded an uptick in new cases. The World Health Organization labelled it Africa's 'Worst Pandemic Week Ever'.


Oceania

The COVID-19 pandemic was confirmed to have reached Oceania on 25 January 2020 with the first confirmed case reported in Melbourne, COVID-19 pandemic in Australia, Australia. It has since spread elsewhere in the region, although many small Pacific island country, island nations have thus far avoided the outbreak by closing their international borders. Two Oceania sovereign states (Nauru and Tuvalu) and one dependency (COVID-19 pandemic in the Cook Islands, Cook Islands) have yet to report an active case. COVID-19 pandemic in Australia, Australia and COVID-19 pandemic in New Zealand, New Zealand were praised for their handling of the pandemic in comparison to other Western nations, with New Zealand and each state in Australia wiping out all community transmission of the virus several times even after re-introduction in the community. As a result of the high transmissibility of the Delta variant however, by August 2021, the Australian states of New South Wales and Victoria (Australia), Victoria had conceded defeat in their eradication efforts. In early October 2021, New Zealand also abandoned its elimination strategy.


Antarctica

Due to its remoteness and sparse population, Antarctica was the last continent to have confirmed cases of COVID-19 and was one of the last regions of the world affected directly by the pandemic. The first cases were reported in December 2020, almost a year after the first cases of COVID-19 were detected in China. At least 36 people are confirmed to have been infected.


Responses

The pandemic shook the world's economy, with especially severe economic damage in the United States, Europe, and Latin America. A consensus report by American intelligence agencies in April 2021 concluded, "Efforts to contain and manage the virus have reinforced nationalist trends globally, as some states turned inward to protect their citizens and sometimes cast blame on marginalized groups." COVID-19 inflamed partisanship and polarisation around the world as bitter arguments exploded over how to respond. International trade was disrupted amid the formation of no-entry enclaves.


Travel restrictions

The pandemic led many countries and regions to impose quarantines, entry bans, or other restrictions, either for citizens, recent travellers to affected areas, or for all travellers. Travel collapsed worldwide, damaging the travel sector. The effectiveness of travel restrictions was questioned as the virus spread across the world. One study found that travel restrictions only modestly affected the initial spread, unless combined with other infection prevention and control measures. Researchers concluded that "travel restrictions are most useful in the early and late phase of an epidemic" and "restrictions of travel from Wuhan unfortunately came too late". The European Union rejected the idea of suspending the Schengen Agreement, Schengen free travel zone.


Repatriation of foreign citizens

Several countries repatriated their citizens and diplomatic staff from Wuhan and surroundings, primarily through Air charter, charter flights. Canada, the United States, Japan, India, Sri Lanka, Australia, France, Argentina, Germany, and Thailand were among the first to do so. Brazil and New Zealand evacuated their own nationals and others. On 14 March, South Africa repatriated 112 South Africans who tested negative, while four who showed symptoms were left behind. Pakistan declined to evacuate its citizens. On 15 February, the US announced it would evacuate Americans aboard the Diamond Princess outbreak, Diamond Princess cruise ship, and on 21 February, Canada evacuated 129 Canadians from the ship. In early March, the Indian government began repatriating its citizens from Iran. On 20 March, the United States began to withdraw some troops from Iraq.


United Nations

In June 2020, the Secretary-General of the United Nations launched the UN Comprehensive Response to COVID-19. The United Nations Conference on Trade and Development (UNSC) was criticised for its slow response, especially regarding the UN's global ceasefire, which aimed to open up humanitarian access to conflict zones.


WHO

The WHO spearheaded initiatives such as the COVID-19 Solidarity Response Fund to raise money for the pandemic response, the UN COVID-19 Supply Chain Task Force, and the solidarity trial for investigating potential treatment options for the disease. The COVAX program, co-led by the WHO, GAVI, Gavi, and the Coalition for Epidemic Preparedness Innovations (CEPI), aimed to accelerate the development, manufacture, and distribution of COVID-19 vaccines, and to guarantee fair and equitable access across the world.


Protests against governmental measures

In several countries, protests rose against restrictions such as lockdowns. A February 2021 study found that protests against restrictions were likely to directly increase spread.


Impact


Economics

The pandemic and responses to it damaged the global economy. On 27 February, worries about the outbreak crushed US stock indexes, which posted their sharpest falls since 2008. Tourism collapsed due to travel restrictions, closing of public places including travel attractions, and advice of governments against travel. Airlines cancelled flights, while British regional airline Flybe collapsed. The cruise line industry was hard hit, and train stations and ferry ports closed. International mail stopped or was delayed. The retail sector faced reductions in store hours or closures. Retailers in Europe and Latin America faced traffic declines of 40 per cent. North America and Middle East retailers saw a 50–60 per cent drop. Shopping centres faced a 33–43 per cent drop in foot traffic in March compared to February. Mall operators around the world coped by increasing sanitation, installing thermal scanners to check the temperature of shoppers, and cancelling events. Hundreds of millions of jobs were lost. including more than 40 million Americans. According to a report by Yelp, about 60% of US businesses that closed will stay shut permanently. The International Labour Organization (ILO) reported that the income generated in the first nine months of 2020 from work across the world dropped by 10.7 per cent, or $3.5 trillion.


Supply shortages

The outbreak was blamed for
panic buying Panic buying (alternatively hyphenated as panic-buying; also known as panic purchasing) occurs when consumer A consumer is a person or a group who intends to order, orders, or uses purchased goods, products, or Service (economics), services pri ...
, emptying groceries of essentials such as food, toilet paper, and bottled water. Panic buying stemmed from perceived threat, perceived scarcity, fear of the unknown, coping behaviour and social psychological factors (e.g. social influence and trust). Shortage, Supply shortages were due to disruption to factory and logistic operations; shortages were worsened by
supply chain In , a supply chain is a system of organizations, people, activities, information, and resources involved in supplying a or to a consumer. Supply chain activities involve the transformation of s, s, and components into a finished product and de ...

supply chain
disruptions from factory and port shutdowns, and labour shortages. Shortages continued as managers underestimated the speed of economic recovery after the initial economic crash. The technology industry, in particular, warned of delays from underestimates of semiconductor demand for vehicles and other products. According to WHO's Adhanom, demand for personal protective equipment (PPE) rose one hundredfold, pushing prices up twentyfold. PPE stocks were exhausted everywhere. In September 2021, the World Bank reported that food prices remain generally stable and the supply outlook remains positive. However, the poorest countries witnessed a sharp increase in food prices, reaching the highest level since the pandemic began. The Agricultural Commodity Price Index stabilized in the third quarter but remained 17% higher than in January 2021. By contrast, petroleum products were in surplus at the beginning of the pandemic, as demand for gasoline and other products collapsed due to reduced commuting and other trips.US oil prices turn negative as demand dries up
BBC, 21 April 2020.
The 2021 global energy crisis was driven by a global surge in demand as the world economy recovered. Energy demand was particularly strong in Asia.


Culture

The performing arts and cultural heritage sectors have been profoundly affected by the pandemic, impacting organisations' operations as well as individuals—both employed and independent—globally. By March 2020, across the world and to varying degrees, museums, libraries, performance venues, and other cultural institutions had been indefinitely closed with their exhibitions, events and performances cancelled or postponed. Some services continued through digital platforms, such as live streaming concerts or web-based arts festivals.


Politics

The pandemic affected political systems, causing suspensions of legislative activities, isolations or deaths of politicians, and rescheduled elections. Although they developed broad support among epidemiologists, NPIs (non-pharmaceutical interventions) were controversial in many countries. Intellectual opposition came primarily from other fields, along with heterodox epidemiologists.''The Economist'', 4 April 2020, page 14. On 23 March 2020, United Nations Secretary-General António Guterres, António Manuel de Oliveira Guterres appealed for a global ceasefire; 172 UN member states and observers signed a non-binding supporting statement in June, and the UN Security Council passed a United Nations Security Council Resolution 2532, resolution supporting it in July.


China

Multiple provincial-level administrators of the Communist Party of China were dismissed over their handling of quarantine measures. Some commentators claimed this move was intended to protect CCP General Secretary of the Communist Party, general secretary Xi Jinping. The US intelligence community claimed that China intentionally under-reported its COVID-19 caseload. The Chinese government maintained that it acted swiftly and transparently. Journalists and activists in China who reported on the pandemic were detained by authorities, including Zhang Zhan, who was arrested and tortured.


Italy

In early March, the Italian government criticised the EU's lack of solidarity with Italy. On 22 March, after a phone call with Italian Prime Minister Giuseppe Conte, Russian president Vladimir Putin ordered the Russian Armed Forces, Russian army to send military medics, disinfection vehicles, and other medical equipment to Italy. In early April, Norway and EU states like Romania and Austria started to offer help by sending medical personnel and disinfectant, and Ursula von der Leyen offered an official apology to the country.


United States

The outbreak prompted calls for the United States to adopt social policies common in other wealthy countries, including universal health care, universal child care, paid sick leave, and higher levels of funding for public health. Some political analysts claimed that the pandemic contributed to President Donald Trump, Donald Trump's 2020 United States presidential election, 2020 defeat. Beginning in mid-April 2020, protestors objected to government-imposed business closures and restricted personal movement and association."Coronavirus: Anti-Lockdown Protests Grow Across US". BBC News. 17 April 2020
Archived
from the original on 17 April 2020. Retrieved 17 April 2020.
Simultaneously, essential workers protested in the form of a brief 2020 United States essential workers general strike, general strike.


Other countries

The number of journalists imprisoned or detained increased worldwide, with some related to the pandemic. The planned NATO "List of NATO exercises, Defender 2020" military exercise in Germany, Poland, and the Baltic states, the largest NATO war exercise since the end of the Cold War, was held on a reduced scale. The Iranian government was heavily affected by the virus, which infected some two dozen parliament members and political figures. Iran President Hassan Rouhani, Hassan Rouhani wrote a public letter to world leaders asking for help on 14 March 2020, due to a lack of access to international markets. Saudi Arabia, which launched a Saudi Arabian-led intervention in Yemen, military intervention in Yemen in March 2015, declared a ceasefire. Japan–South Korea relations, Diplomatic relations between Japan and South Korea worsened. South Korea criticised Japan's "ambiguous and passive quarantine efforts" after Japan announced travellers from South Korea must quarantine for two weeks. South Korean society was initially polarised on President Moon Jae-in's response to the crisis; many Koreans signed petitions calling for Moon's impeachment or praising his response. Some countries passed emergency legislation. Some commentators expressed concern that it could allow governments to strengthen their grip on power. In the Philippines, lawmakers granted President Rodrigo Duterte temporary emergency powers. In Hungary, the parliament voted to allow prime minister Viktor Orbán to rule by decree indefinitely, suspend parliament and elections, and punish those deemed to have spread false information. In countries such as Egypt, Turkey, and Thailand, opposition activists and government critics were Misinformation related to the COVID-19 pandemic#Efforts to combat misinformation, arrested for allegedly spreading fake news. In India, journalists criticising the government's response were arrested or issued warnings by police and authorities.


Food systems

The pandemic disrupted food systems worldwide, hitting at a time when hunger/undernourishment was rising (an estimated 690 million people lacked food security in 2019). Food access fell – driven by falling incomes, lost remittances, and disruptions to food production. In some cases, food prices rose. The pandemic and its accompanying lockdowns and travel restrictions slowed movement of food aid. Per the World Health Organization 811 million individuals were undernourished in 2020, "likely related to the fallout of COVID-19".


Education

The pandemic impacted educational systems in many countries. Many governments temporarily closed educational institutions, often replaced by online education. Other countries, such as Sweden, kept their schools open. As of September 2020, approximately 1.077 billion Learning, learners were affected due to school closures. School closures impacted students, teachers, and families with far-reaching economic and societal consequences. They shed light on social and economic issues, including student debt, digital learning, food insecurity, and homelessness, as well as access to Child care, childcare, health care, housing, internet, and Disability rights movement, disability services. The impact was more severe for disadvantaged children. The Higher Education Policy Institute reported that around 63% of students claimed worsened mental health as a result of the pandemic.


Health

The pandemic impacted global health for many other conditions. Hospital visits fell. Visits for heart attack symptoms declined by 38%, in the US and 40% in Spain. The head of cardiology at the University of Arizona said, "My worry is some of these people are dying at home because they're too scared to go to the hospital."'Where are all our patients?': Covid phobia is keeping people with serious heart symptoms away from ERs
''Stat News'', Usha Lee McFarling, 23 April 2020.
People with strokes and appendicitis were less likely to seek treatment. Shortages related to the COVID-19 pandemic, Medical supply shortages impacted many people. The pandemic impacted mental health, increasing anxiety, Depression (mood), depression, and post-traumatic stress disorder, affecting healthcare workers, patients and quarantined individuals.


Environment

The pandemic and the reaction to it positively affected the Natural environment, environment and climate as a result of reduced human activity. During the "anthropause", fossil fuel use decreased, resource consumption declined, and waste disposal improved, generating less pollution. Economic impact of the COVID-19 pandemic#Transportation, Planned air travel and vehicle transportation declined. In China, COVID-19 lockdown in Hubei, lockdowns and other measures resulted in a 26% decrease in coal consumption, and a 50% reduction in nitrogen oxides emissions. Earth system science, Earth systems scientist Marshall Burke estimated that two months of pollution reduction likely saved the lives of 77,000 Chinese residents.


Discrimination and prejudice

Heightened prejudice, xenophobia, and racism Sinophobe, toward people of Chinese and East Asian descent were documented around the world. Reports from February 2020 (when most confirmed cases were confined to China) cited racist sentiments about Chinese people 'deserving' the virus. Chinese people and other Asian peoples in the United Kingdom and United States reported increasing levels of abuse and assaults. Former US President Trump was criticised for referring to SARS-CoV-2 as the "Chinese Virus" and "Kung Flu", which others condemned as racist and xenophobic. Age-based discrimination against older adults increased. This was attributed to their perceived vulnerability and subsequent physical and social isolation measures, which, coupled with their reduced social activity, increased dependency on others. Similarly, limited digital literacy left the elderly more vulnerable to isolation, depression, and loneliness.


Lifestyle changes

The pandemic triggered massive changes in behaviour, from increased internet commerce to the job market. Online retailers in the US posted 791.70 billion dollars in sales in 2020, an increase of 32.4% from 598.02 billion dollars from the year before. Home delivery orders increased, while indoor restaurant dining shut down due to lockdown orders or low sales. Hackers and cybercriminals/scammers took advantage of the changes to launch new attacks. Education in some countries temporarily shifted from physical attendance to video conferencing. Massive layoffs shrank the airline, travel, hospitality, and other industries.


Information dissemination

Research is indexed and searchable in the NIH COVID-19 Portfolio. Some newspaper agencies removed their online paywalls for some or all of their pandemic-related articles and posts, Some scientific publishers made pandemic-related papers available with open access. The share of papers published on preprint servers prior to peer review increased dramatically.


Misinformation

Misinformation and conspiracy theory, conspiracy theories about the pandemic were widespread. They travelled through
mass media Mass media refers to a diverse array of media Media may refer to: Physical means Communication * Media (communication), tools used to deliver information or data ** Advertising media, various media, content, buying and placement fo ...
, Impact of the COVID-19 pandemic on social media#Misinformation, social media, and text messaging. WHO declared an "infodemic" of incorrect information. Cognitive biases, such as jumping to conclusions and confirmation bias, were linked to conspiracy beliefs.


See also

* Emerging infectious disease * Globalization and disease * List of epidemics * Coronavirus diseases


Notes


References


Further reading

* * * * * * * * * * * *


External links


Health agencies


COVID-19Questions & Answersinstructional videosFacts/MythBusters
by the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
(WHO)
COVID-19
by the Government of Canada
COVID-19Q&A
by the European Centre for Disease Prevention and Control
COVID-19Q&A
by the Ministry of Health, Singapore
COVID-19
by the US Centers for Disease Control and Prevention (CDC)
COVID-19 Information for the Workplace
by the US National Institute for Occupational Safety and Health (NIOSH)


Directories


COVID-19 Directory on Curlie

COVID-19 Resource Directory on OpenMD


Data and graphs


Coronavirus disease (COVID-19) situation reports
an
map
by the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unite ...
(WHO)
COVID-19 Resource Center
an
historical data
by
Johns Hopkins University The Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty S ...

Johns Hopkins University

COVID-19 data sets
published by the European Centre for Disease Prevention and Control (ECDC)
COVID-19 Observer
based on
Johns Hopkins University The Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty S ...

Johns Hopkins University
data
COVID-19 Statistics and Research
published by Our World in Data
COVID-19 Tracker
from Stat (website), Stat News
COVID-19 Projections
for many countries published by
Institute for Health Metrics and Evaluation The Institute for Health Metrics and Evaluation (IHME) is a research institute working in the area of global health statistics and impact evaluation at the University of Washington in Seattle. The Institute is headed by Christopher J.L. Murray, ...

Spreadsheets: Country comparisons



World Travel Restrictions
based on World Food Programme (WFP) data


Medical journals


Coronavirus (COVID-19)
by ''The New England Journal of Medicine''
Coronavirus (COVID-19) Hub
by BMJ (company), BMJ Publishing Group
Coronavirus Disease 2019 (COVID-19)
by ''JAMA (journal), JAMA: The Journal of the American Medical Association''
COVID-19: Novel Coronavirus Outbreak
by Wiley (publisher), Wiley Publishing
COVID-19 pandemic (2019–20) Collection
by Public Library of Science (PLOS)
COVID-19 Portfolio
a curated collection of publications and preprints by National Institutes of Health (NIH)
COVID-19 Research Highlights
by Springer Nature
COVID-19 Resource Centre
by ''The Lancet''
Novel Coronavirus Information Center
by Elsevier {{subject bar, b = y, b-search = COVID-19, commons = y, commons-search = COVID-19 pandemic, d = y, d-search = COVID-19, n = y, n-search = COVID-19, q = y, q-search = COVID-19 pandemic, s = y, s-search = COVID-19, species = y, species-search = COVID-19, v = y, v-search = COVID-19, voy = y, voy-search = COVID-19 pandemic, wikt = y, wikt-search = COVID-19, portal1=COVID-19, portal2=Current events, portal3=Viruses, portal4=World COVID-19 pandemic, 2010s disease outbreaks 2020s disease outbreaks 2020s economic history 21st-century epidemics 21st-century health disasters 21st century in health 2019 disasters 2019 disasters in China 2019 health disasters 2019 in international relations 2020 disasters 2020 health disasters 2020 in international relations 2021 disasters 2021 health disasters 2021 in international relations 2022 disasters 2022 health disasters 2022 in international relations December 2019 events in China January 2020 events in China February 2020 events in China March 2020 events in China Articles containing video clips Atypical pneumonias Health disasters in China History of Wuhan Occupational safety and health Pandemics Public Health Emergency of International Concern