An outline, era by era

COVID-19 pandemic (2020 – 2023)

21st Century · 2000 – present

The COVID-19 pandemic was a global outbreak of the disease caused by the coronavirus SARS-CoV-2. The first known cluster of cases appeared in Wuhan, China, in December 2019. The virus spread to every inhabited continent within a few months, and the World Health Organization declared a pandemic on 11 March 2020. On 5 May 2023 the World Health Organization ended its highest level of emergency for COVID-19. This did not formally end the pandemic, but the date is commonly used as a convention for its end.

The pandemic caused millions of recorded deaths, and estimates of excess deaths are considerably higher. Governments closed borders, schools and workplaces, and many people worked and studied from home. Vaccines were developed in under a year, and the economic and social effects were large and uneven. The pandemic changed public health, work and politics, and it left lasting debates about how it began and how it was handled.

Things happened, and the rest is history

  1. The Wuhan cluster and the first alert

    Event

    What happened

    In December 2019 doctors in Wuhan, Hubei province, report a cluster of patients with an unexplained pneumonia, many linked to the Huanan Seafood Market. On 31 December 2019 the Wuhan health commission announces the cases publicly, and the World Health Organization is informed. On 7 January 2020 Chinese scientists identify a new coronavirus, and its genome sequence is shared publicly on 10 to 11 January.

    The rest is history

    The early sharing of the genome allowed laboratories around the world to build tests and begin vaccine work within days. Local officials were criticised for slow reporting and for reprimanding doctors who raised the alarm, including Li Wenliang, who later died of the disease in February 2020. The exact origin of the virus remains debated. The WHO's advisory group on the origins of new pathogens has concluded that the available evidence is not enough to rule out either a natural spillover from animals or a laboratory-related origin. Wuhan was placed under lockdown on 23 January 2020.

    Sources

    1. PrimaryWorld Health Organization. Novel Coronavirus (2019-nCoV) Situation Report 1. Geneva: WHO, 21 January 2020.
    2. ArticleZhu, Na, et al. "A Novel Coronavirus from Patients with Pneumonia in China, 2019." New England Journal of Medicine 382, no. 8 (2020): 727-733.

  2. Earlier coronavirus outbreaks: SARS and MERS

    Event

    What happened

    In 2002 to 2003 an outbreak of severe acute respiratory syndrome, SARS, caused by a coronavirus, spreads from southern China to more than two dozen countries and is contained by mid-2003. In 2012 another coronavirus disease, Middle East respiratory syndrome, MERS, is identified in Saudi Arabia, and it causes repeated outbreaks.

    The rest is history

    These outbreaks showed that coronaviruses could jump from animals to people and cause serious disease. They led to research on coronavirus vaccines and to reforms such as the revised International Health Regulations of 2005. Much of this earlier work, including studies of the spike protein, helped scientists move quickly on SARS-CoV-2 in 2020. SARS was far deadlier per case but spread much less widely than COVID-19.

    Sources

    1. PrimaryWorld Health Organization. Summary of Probable SARS Cases with Onset of Illness from 1 November 2002 to 31 July 2003. Geneva: WHO, 2003.
    2. BookQuammen, David. Spillover: Animal Infections and the Next Human Pandemic. New York: W. W. Norton, 2012.

  3. The 2005 International Health Regulations

    Event

    What happened

    In May 2005 the World Health Assembly adopts a revised set of International Health Regulations, in force from 2007. They require countries to build capacity to detect and report health threats, and they create the category of a public health emergency of international concern.

    The rest is history

    This framework governed the response to COVID-19. The WHO declared a public health emergency of international concern on 30 January 2020, before the pandemic declaration of 11 March. Reviews afterwards found that many countries had not built the capacity the rules asked for, and that the system of alerts was slow to prompt action. Negotiations on a separate pandemic agreement began in 2021 as a result.

    Sources

    1. PrimaryInternational Health Regulations (2005). Adopted by the World Health Assembly, 23 May 2005. Geneva: World Health Organization.

  4. Lockdowns and border closures

    Event

    What happened

    On 23 January 2020 China locks down Wuhan, a city of about eleven million people. Italy locks down its north in early March and the whole country on 9 March 2020. Within weeks, dozens of countries close schools, limit travel and order people to stay home, and international air travel falls sharply.

    The rest is history

    Lockdowns slowed the early spread of the virus and eased pressure on hospitals in many places, but they also caused large economic losses, disrupted schooling and affected mental health. Governments differed widely in how strict they were, and scholars still debate which measures worked best. Global economic output fell in 2020 by an amount the International Monetary Fund put at about 3 percent, the sharpest fall since the Great Depression apart from wartime.

    Sources

    1. PrimaryDecree of the President of the Council of Ministers, 9 March 2020. Gazzetta Ufficiale della Repubblica Italiana, no. 62, 9 March 2020.
    2. ArticleHale, Thomas, et al. "A Global Panel Database of Pandemic Policies (Oxford COVID-19 Government Response Tracker)." Nature Human Behaviour 5 (2021): 529-538.

  5. The pandemic declaration of March 2020

    Event

    What happened

    On 11 March 2020 the WHO director-general, Tedros Adhanom Ghebreyesus, says COVID-19 can be characterised as a pandemic, citing more than 118,000 cases in 114 countries. In the following days the United States and many European countries declare national emergencies and close schools and public events.

    The rest is history

    The declaration marked the point when many governments moved from watching to acting. Hospitals in northern Italy, New York and elsewhere were overwhelmed in the spring of 2020, and shortages of masks and tests became a major problem. Reported deaths passed a million by September 2020. The WHO later estimated that excess deaths in 2020 and 2021 together were around 14.9 million, though such estimates are contested.

    Sources

    1. PrimaryTedros Adhanom Ghebreyesus. WHO Director-General's opening remarks at the media briefing on COVID-19, 11 March 2020. Geneva: WHO.
    2. BookWright, Lawrence. The Plague Year: America in the Time of Covid. New York: Alfred A. Knopf, 2021.

  6. Vaccines developed in record time

    Event

    What happened

    Chinese scientists publish the virus genome in January 2020, and vaccine developers begin work at once. In the United States, Operation Warp Speed funds several candidates. On 2 December 2020 the United Kingdom authorises the Pfizer-BioNTech mRNA vaccine, and the United States issues an emergency authorisation on 11 December. Other vaccines, including those of Moderna, Oxford-AstraZeneca, Sinovac and Sputnik V, follow.

    The rest is history

    No vaccine had previously been developed so quickly, and the work built on decades of research on mRNA and coronaviruses. Vaccines greatly reduced severe disease and death, and one study estimated that they saved about 14 million lives in their first year. Distribution was very unequal, with wealthy countries vaccinating far earlier than poor ones. The COVAX scheme, begun in 2020, tried to share doses but fell short of its goals.

    Sources

    1. ArticlePolack, Fernando P., et al. "Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine." New England Journal of Medicine 383, no. 27 (2020): 2603-2615.
    2. ArticleWatson, Oliver J., et al. "Global Impact of the First Year of COVID-19 Vaccination." The Lancet Infectious Diseases 22, no. 9 (2022): 1293-1302.

  7. Variants and successive waves

    Event

    What happened

    In late 2020 the Alpha variant is identified in the United Kingdom and Beta in South Africa. Delta, first found in India, drives a severe wave in spring 2021. In November 2021 Omicron is reported in southern Africa, and it spreads around the world within weeks.

    The rest is history

    Each variant changed the course of the pandemic. Omicron was far more transmissible and better at evading immunity, though on average it caused less severe illness in vaccinated people. The WHO adopted Greek letters to name variants in May 2021 to avoid naming them after places. By 2022 high levels of immunity from vaccination and infection meant many countries began to drop restrictions.

    Sources

    1. PrimaryWorld Health Organization. Classification of Omicron (B.1.1.529) as a Variant of Concern. Statement, Geneva, 26 November 2021.
    2. ArticleViana, Raquel, et al. "Rapid Epidemic Expansion of the SARS-CoV-2 Omicron Variant in Southern Africa." Nature 603 (2022): 679-686.

  8. The end of the global emergency

    Event

    What happened

    On 5 May 2023 the WHO director-general announces, on the advice of its emergency committee, that COVID-19 no longer constitutes a public health emergency of international concern. He stresses that this does not mean the disease has stopped being a threat. The United States ended its national emergency declaration on 10 April 2023 and its federal public health emergency on 11 May 2023.

    The rest is history

    The decision followed declining deaths and high population immunity. The virus continued to circulate and cause deaths, and many people suffered long-term symptoms known as long COVID. Independent reviews of the response called for stronger early warning, fairer access to vaccines and better data sharing. Negotiations on a WHO pandemic agreement, begun in 2021, continued after the emergency ended.

    Sources

    1. PrimaryTedros Adhanom Ghebreyesus. WHO Director-General's opening remarks at the media briefing, 5 May 2023. Geneva: WHO.
    2. PrimaryIndependent Panel for Pandemic Preparedness and Response. COVID-19: Make it the Last Pandemic. Report, May 2021.

  9. Drinking or injecting disinfectant as a cure

    Popular belief

    The legend

    Early in the pandemic many people repeat the claim that swallowing or injecting disinfectant, or drinking bleach, can kill the virus in the body. The claim spreads on social media and is boosted by remarks at a White House briefing on 23 April 2020.

    The rest is history

    Disinfectants are poisonous when swallowed or injected, and health agencies warned against the practice at once. Poison control centres in the United States reported a rise in calls about cleaning products in early 2020, and one US Centers for Disease Control and Prevention survey that June found that some respondents reported unsafe practices. The president later said he had been speaking sarcastically. The episode became a standard example of the health misinformation that the WHO called an infodemic in 2020.

    Sources

    1. ArticleGharpure, Radhika, et al. "Knowledge and Practices Regarding Safe Household Cleaning and Disinfection for COVID-19 Prevention." Morbidity and Mortality Weekly Report 69, no. 23 (2020): 705-709.
    2. PrimaryWorld Health Organization. Novel Coronavirus (2019-nCoV) Situation Report 13. Geneva: WHO, 2 February 2020.First WHO use of the term infodemic.

  10. 5G towers spread the virus

    Popular belief

    The legend

    In early 2020 a story spreads online that 5G mobile phone networks cause COVID-19 or weaken the immune system, so that the virus is a cover for the new technology. Some versions say the outbreak began where 5G was first switched on.

    The rest is history

    Viruses cannot travel on radio waves, and COVID-19 spread widely in countries with no 5G. The WHO and many governments rejected the claim. In April 2020 people set fire to mobile phone masts in the United Kingdom and elsewhere, and engineers were harassed. Fact-checking groups traced the story to social media posts in January 2020.

    Sources

    1. PrimaryWorld Health Organization. Coronavirus Disease (COVID-19) Advice for the Public: Mythbusters. Geneva: WHO, 2020.States that viruses cannot travel on radio waves or mobile networks.
    2. ArticleAhmed, Wasim, et al. "COVID-19 and the 5G Conspiracy Theory: Social Network Analysis of Twitter Data." Journal of Medical Internet Research 22, no. 5 (2020): e19458.

  11. Hydroxychloroquine as a miracle cure

    Popular belief

    The legend

    In March 2020 the malaria drug hydroxychloroquine is widely promoted as a cure or preventive for COVID-19, and people in several countries buy up supplies.

    The rest is history

    Early laboratory work and a small French study in March 2020 raised hopes. Large randomised trials, including the RECOVERY trial in the United Kingdom and the WHO Solidarity trial, found that the drug did not reduce deaths in hospitalised patients. The US Food and Drug Administration withdrew its emergency authorisation on 15 June 2020. By contrast, the steroid dexamethasone was shown by RECOVERY in June 2020 to lower deaths among patients needing oxygen.

    Sources

    1. ArticleHorby, Peter, et al. "Effect of Hydroxychloroquine in Hospitalized Patients with Covid-19." New England Journal of Medicine 383, no. 21 (2020): 2030-2040.
    2. ArticleGautret, Philippe, et al. "Hydroxychloroquine and Azithromycin as a Treatment of COVID-19." International Journal of Antimicrobial Agents 56, no. 1 (2020): 105949.

  12. Vaccines contain microchips

    Popular belief

    The legend

    In 2020 and 2021 a claim spreads that COVID-19 vaccines contain microchips, put there to track people. It is linked to a story that the Microsoft founder Bill Gates planned this.

    The rest is history

    The ingredients of the authorised vaccines are published, and none of them lists a tracking device. The claim grew out of a March 2020 online interview in which Gates discussed digital certificates of vaccination, and a research paper on a dye that could record vaccination marks in the skin. Fact-checkers and health agencies repeatedly rejected the claim.

    Sources

    1. PrimaryPfizer-BioNTech COVID-19 Vaccine: Fact Sheet for Recipients and Caregivers. US Food and Drug Administration, December 2020.Lists the ingredients.

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