COVID-19

== History ==
{{update section|reason=excessive detail about the very early pandemic while missing an overview of the later pandemic|date=July 2023}}
{{Main|Timeline of the COVID-19 pandemic|Investigations into the origin of COVID-19}}
{{COVID-19 pandemic sidebar}}
The virus is thought to be of natural animal origin, most likely through [[spillover infection]].<ref name="NM-20200317">{{#invoke:cite journal || vauthors = Andersen KG, Rambaut A, Lipkin WI, Holmes EC, Garry RF | title = The proximal origin of SARS-CoV-2 | journal = Nature Medicine | volume = 26 | issue = 4 | pages = 450–452 | date = April 2020 | pmid = 32284615 | pmc = 7095063 | doi = 10.1038/s41591-020-0820-9 }}</ref><ref name="PMC7969828">{{#invoke:cite journal || vauthors = Frutos R, Gavotte L, Devaux CA | title = Understanding the origin of COVID-19 requires to change the paradigm on zoonotic emergence from the spillover to the circulation model | journal = Infection, Genetics and Evolution | volume = 95 | pages = 104812 | date = November 2021 | pmid = 33744401 | pmc = 7969828 | doi = 10.1016/j.meegid.2021.104812 }}</ref><ref>{{#invoke:cite journal || vauthors = Holmes EC, Goldstein SA, Rasmussen AL, Robertson DL, Crits-Christoph A, Wertheim JO, Anthony SJ, Barclay WS, Boni MF, Doherty PC, Farrar J, Geoghegan JL, Jiang X, Leibowitz JL, Neil SJ, Skern T, Weiss SR, Worobey M, Andersen KG, Garry RF, Rambaut A  | title = The origins of SARS-CoV-2: A critical review | journal = Cell | volume = 184 | issue = 19 | pages = 4848–4856 | date = September 2021 | pmid = 34480864 | pmc = 8373617 | doi = 10.1016/j.cell.2021.08.017 }}</ref> A joint-study conducted in early 2021 by the People's Republic of China and the [[World Health Organization]] indicated that the virus descended from a coronavirus that infects wild bats, and likely spread to humans through an intermediary wildlife host.<ref>{{#invoke:Cite web||url=https://www.who.int/publications/i/item/who-convened-global-study-of-origins-of-sars-cov-2-china-part|work=[[World Health Organization]]|title=WHO-convened Global Study of Origins of SARS-CoV-2: China Part|date=30 March 2021|access-date=29 July 2022}}</ref> There are several theories about where the [[index case]] originated and [[Investigations into the origin of COVID-19|investigations into the origin of the pandemic]] are ongoing.<ref name="patientZero">{{#invoke:cite news|| vauthors = Duarte F | date=24 February 2020|title=As the cases of coronavirus increase in China and around the world, the hunt is on to identify "patient zero".|work=BBC News|url=https://www.bbc.com/future/article/20200221-coronavirus-the-harmful-hunt-for-covid-19s-patient-zero|access-date=22 March 2020}}</ref> According to articles published in July 2022 in ''[[Science (journal)|Science]]'', virus transmission into humans occurred through two spillover events in November 2019 and was likely due to live wildlife trade on the [[Huanan Seafood Wholesale Market|Huanan wet market]] in the city of [[Wuhan]] (Hubei, China).<ref>{{#invoke:cite journal||title=The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2 |date=26 July 2022 |journal=[[Science (journal)|Science]]|vauthors=Pekar JE, Magee P, Parker E, Moshiri N, Izhikevich K, Havens JL, Gangavarapu K, Serrano LM, Crits-Christoph A, Matteson NL, Zeller M, Levy JI, Wang JC, Hughes S, Lee JM, Park H, Park MS, Ching ZY, Lin TP, Isa NM, Noor YM, Vasylyeva TI, Garry RF, Holmes EC, Rambaut A, Suchard MA, Andersen KG, Worobey M, Wertheim JO|pages=960–966 |doi-access = free | title-link = doi |volume=377 |issue=6609 |doi=10.1126/science.abp8337|pmid=35881005 |pmc=9348752 |bibcode=2022Sci...377..960P }}</ref><ref>{{#invoke:Cite news ||last=Gill |first=Victoria |date=26 July 2022 |title=Covid origin studies say evidence points to Wuhan market |work=[[BBC News Online]] |publisher=[[BBC]] |url=https://www.bbc.com/news/science-environment-62307383 |url-status=live |access-date=31 August 2023 |archive-url=https://web.archive.org/web/20220726153445/https://www.bbc.com/news/science-environment-62307383 |archive-date=26 July 2022}}</ref><ref>{{#invoke:cite journal ||title=The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic |date=July 2022 |journal=Science |doi=10.1126/science.abp8715 | vauthors = Worobey M, Levy JI, Serrano LM, Crits-Christoph A, Pekar JE, Goldstein SA, Rasmussen AL, Kraemer MU, Newman C, Koopmans MP, Suchard MA, Wertheim JO, Lemey P, Robertson DL, Garry RF, Holmes EC, Rambaut A, Andersen KG | title-link=doi |volume=377 |issue=6609 |pages=951–959 |pmid=35881010 |pmc=9348750 |bibcode=2022Sci...377..951W |s2cid=251067542 }}</ref> Doubts about the conclusions have mostly centered on the precise site of spillover.<ref>{{#invoke:cite news ||url=https://www.nationalgeographic.com/magazine/article/debate-deepens-over-wuhan-wet-markets-role-in-kickstarting-the-pandemic |title=Debate deepens over Wuhan wet market's role in kickstarting the pandemic |date=27 July 2022 |work=[[National Geographic]]}}</ref> Earlier [[phylogenetics]] estimated that SARS-CoV-2 arose in October or November 2019.<ref name="evolutionary">{{#invoke:cite journal || vauthors = Li X, Zai J, Zhao Q, Nie Q, Li Y, Foley BT, Chaillon A  | title = Evolutionary history, potential intermediate animal host, and cross-species analyses of SARS-CoV-2 | journal = Journal of Medical Virology | volume = 92 | issue = 6 | pages = 602–611 | date = June 2020 | pmid = 32104911 | pmc = 7228310 | doi = 10.1002/jmv.25731 }}</ref><ref name="zoonotic">{{#invoke:cite journal || vauthors = Andersen KG, Rambaut A, Lipkin WI, Holmes EC, Garry RF | title = The proximal origin of SARS-CoV-2 | journal = Nature Medicine | volume = 26 | issue = 4 | pages = 450–452 | date = April 2020 | pmid = 32284615 | pmc = 7095063 | doi = 10.1038/s41591-020-0820-9 | title-link = doi | doi-access = free }}</ref><ref name="dorp_evo">{{#invoke:cite journal || vauthors = van Dorp L, Acman M, Richard D, Shaw LP, Ford CE, Ormond L, Owen CJ, Pang J, Tan CC, Boshier FA, Ortiz AT, Balloux F  | title = Emergence of genomic diversity and recurrent mutations in SARS-CoV-2 | journal = Infection, Genetics and Evolution | volume = 83 | pages = 104351 | date = September 2020 | pmid = 32387564 | pmc = 7199730 | doi = 10.1016/j.meegid.2020.104351 }}</ref> A phylogenetic algorithm analysis suggested that the virus may have been circulating in [[Guangdong]] before Wuhan.<ref>{{#invoke:cite news || vauthors = Grose TK
|url= https://www.usnews.com/news/best-countries/articles/2020-05-13/scientist-suggests-coronavirus-originated-outside-of-wuhan |title=Did the Coronavirus Originate Outside of Wuhan? |work=U.S. News & World Report |date=13 May 2020}}</ref>

Most scientists believe the virus spilled into human populations through natural [[zoonosis]], similar to the [[SARS-CoV-1]] and [[MERS-CoV]] outbreaks, and consistent with other pandemics in human history.<ref name="pekar">{{#invoke:cite journal ||last1=Pekar |first1=Jonathan |title=The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2 |journal=Science |date=26 July 2022 |volume=377 |issue=6609 |pages=960–966 |doi=10.1126/science.abp8337 |pmid=35881005 |pmc=9348752 |bibcode=2022Sci...377..960P }}</ref><ref name="jiang_wang">{{#invoke:cite journal ||last1=Jiang |first1=Xiaowei |last2=Wang |first2=Ruoqi |title=Wildlife trade is likely the source of SARS-CoV-2 |journal=Science |date=25 August 2022 |volume=377 |issue=6609 |pages=925–926 |doi=10.1126/science.add8384 |pmid=36007033 |bibcode=2022Sci...377..925J |s2cid=251843410 |url=https://www.science.org/doi/10.1126/science.add8384 |access-date=20 November 2022}}</ref> According to the [[Intergovernmental Panel on Climate Change]] several social and environmental factors including [[climate change]], [[Environmental degradation|natural ecosystem destruction]] and [[Wildlife trade and zoonoses|wildlife trade]] increased the likelihood of such [[zoonosis|zoonotic spillover]].<ref>{{#invoke:cite book ||title=Terrestrial and Freshwater Ecosystems and Their Services. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |date=2022 |publisher=IPCC |pages=233–235 |url=https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter02.pdf |access-date=14 March 2023}}</ref><ref>{{#invoke:cite book ||title=Health, Wellbeing, and the Changing Structure of Communities. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |date=2022 |publisher=IPCC |pages=1067–1070 |url=https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter07.pdf |access-date=14 March 2023}}</ref> One study made with the support of the [[European Union]] found [[climate change]] increased the likelihood of the pandemic by influencing distribution of bat species.<ref>{{#invoke:cite web ||title=Climate change may have driven the emergence of SARS-CoV-2 |url=https://www.cam.ac.uk/research/news/climate-change-may-have-driven-the-emergence-of-sars-cov-2 |website=University of Cambridge |date=5 February 2021 |publisher=Science of the Total Environment |access-date=14 March 2023}}</ref><ref>{{#invoke:cite web ||title=Climate change the culprit in the COVID-19 pandemic |url=https://cordis.europa.eu/article/id/430229-climate-change-the-culprit-in-the-covid-19-pandemic |website=European Commission |access-date=24 March 2023}}</ref>

Available evidence suggests that the SARS-CoV-2 virus was originally harboured by bats, and spread to humans multiple times from infected wild animals at the [[Huanan Seafood Market]] in [[Wuhan]] in December 2019.<ref name="pekar" /><ref name="jiang_wang" /> A minority of scientists and some members of the [[United States Intelligence Community|U.S intelligence community]] believe the virus may have been [[COVID-19 lab leak theory|unintentionally leaked]] from a laboratory such as the [[Wuhan Institute of Virology]].<ref name="NYT_DoE_Feb2023">{{#invoke:cite web ||last1=Barnes |first1=Julian E. |title=Lab Leak Most Likely Caused Pandemic, Energy Dept. Says |url=https://www.nytimes.com/2023/02/26/us/politics/china-lab-leak-coronavirus-pandemic.html |website=The New York Times |access-date=27 February 2023 |date=26 February 2023}}</ref><ref name="Hill_Feb_2023_DoE">{{#invoke:cite news ||last1=Mueller |first1=Julia |title=Energy Department's COVID lab leak conclusion: What we know |url=https://thehill.com/policy/healthcare/3874965-what-we-know-about-energy-departments-lab-leak-conclusion/ |access-date=26 March 2023 |work=The Hill |date=26 February 2023}}</ref> The US intelligence community has mixed views on the issue,<ref name="CNN_Feb2023_LeBlanc">{{#invoke:cite news ||last1=LeBlanc |first1=Paul |title=New assessment on the origins of Covid-19 adds to the confusion {{!}} CNN Politics |url=https://www.cnn.com/2023/02/27/politics/covid-origins-doe-assessment-what-matters/index.html |access-date=27 February 2023 |work=CNN |date=27 February 2023 |language=en}}</ref><ref name="Guardian_Feb2023">{{#invoke:cite news ||last1=Davis |first1=Nicola |last2=Hawkins |first2=Amy |title=How seriously should we take the US DoE's Covid lab leak theory? |url=https://www.theguardian.com/world/2023/feb/27/how-seriously-should-we-take-the-us-does-covid-lab-leak-theory |access-date=27 February 2023 |work=The Guardian |date=27 February 2023}}</ref> but overall agrees with the scientific consensus that the virus was not developed as a [[Biological agent|biological weapon]] and is unlikely to have been [[Genetic engineering|genetically engineered]].<ref>{{#invoke:Cite web|| vauthors = Wolf ZB |title=Analysis: Why scientists are suddenly more interested in the lab-leak theory of Covid's origin |url=https://www.cnn.com/2021/05/25/politics/wuhan-lab-covid-origin-theory/index.html|access-date=26 May 2021 |publisher=CNN|date=25 May 2021}}</ref><ref>{{#invoke:cite journal ||vauthors=Maxmen A |title=US COVID origins report: researchers pleased with scientific approach |journal=Nature |volume=597 |issue=7875 |pages=159–160 |date=September 2021 |pmid=34465917 |doi=10.1038/d41586-021-02366-0 |s2cid=237373547 |bibcode=2021Natur.597..159M}}</ref><ref>{{#invoke:Cite news||url=https://www.politico.com/newsletters/future-pulse/2022/11/04/cross-examining-the-lab-leak-theorists-00065103|title=Cross-examining the lab-leak theorists|date=4 November 2022|work=[[Politico]] |vauthors=Paun C, Zeller S, Reader R, Leonard B, Scullion G | access-date=21 November 2022 }}</ref><ref>{{#invoke:Cite news||url=https://www.reuters.com/world/us-intelligence-releases-report-covid-19-origins-2021-10-29/|title=U.S. spy agencies say origins of COVID-19 may never be known |vauthors=Hosenball M, Zengerle P|date=30 October 2021 |work=[[Reuters]]|access-date=21 November 2022}}</ref> There is no evidence SARS-CoV-2 existed in any laboratory prior to the pandemic.<ref name=critical>{{#invoke:cite journal ||vauthors=Holmes EC, Goldstein SA, Rasmussen AL, Robertson DL, Crits-Christoph A, Wertheim JO, Anthony SJ, Barclay WS, Boni MF, Doherty PC, Farrar J, Geoghegan JL, Jiang X, Leibowitz JL, Neil SJ, Skern T, Weiss SR, Worobey M, Andersen KG, Garry RF, Rambaut A |title=The origins of SARS-CoV-2: A critical review |journal=Cell |volume=184 |issue=19 |pages=4848–4856 |date=September 2021 |pmid=34480864 |pmc=8373617 |doi=10.1016/j.cell.2021.08.017 |type=Review  |quote=Under any laboratory escape scenario, SARS-CoV-2 would have to have been present in a laboratory prior to the pandemic, yet no evidence exists to support such a notion and no sequence has been identified that could have served as a precursor.}}</ref><ref name="Gorski">{{#invoke:cite web ||last=Gorski |first=David |date=31 May 2021 |title=The origin of SARS-CoV-2, revisited |url=https://sciencebasedmedicine.org/the-origin-of-sars-cov-2-revisited/ |url-status=live |archive-url=https://web.archive.org/web/20210601072923/https://sciencebasedmedicine.org/the-origin-of-sars-cov-2-revisited/ |archive-date=1 June 2021 |access-date=19 July 2021 |publisher=[[Science-Based Medicine]] |quote=The second [version of the lab leak] is the version that "reasonable" people consider plausible, but there is no good evidence for either version.}}</ref><ref name="HolmesConversationDead">{{#invoke:cite web ||last=Holmes |first=Edward C. |date=14 August 2022 |title=The COVID lab leak theory is dead. Here's how we know the virus came from a Wuhan market |url=http://theconversation.com/the-covid-lab-leak-theory-is-dead-heres-how-we-know-the-virus-came-from-a-wuhan-market-188163 |access-date=4 September 2022 |website=The Conversation |language=en |quote=For the lab leak theory to be true, SARS-CoV-2 must have been present in the Wuhan Institute of Virology before the pandemic started. This would convince me. But the inconvenient truth is there's not a single piece of data suggesting this. There's no evidence for a genome sequence or isolate of a precursor virus at the Wuhan Institute of Virology. Not from gene sequence databases, scientific publications, annual reports, student theses, social media, or emails. Even the intelligence community has found nothing. Nothing. And there was no reason to keep any work on a SARS-CoV-2 ancestor secret before the pandemic.}}</ref>

The first confirmed human infections were in Wuhan. A study of the first 41 cases of confirmed COVID‑19, published in January 2020 in ''The Lancet'', reported the earliest date of onset of symptoms as 1{{spaces}}December 2019.<ref name="WuMarch2020">{{#invoke:cite journal ||vauthors=Wu YC, Chen CS, Chan YJ |title=The outbreak of COVID-19: An overview |journal=Journal of the Chinese Medical Association |volume=83 |issue=3 |pages=217–220 |date=March 2020 |pmid=32134861 |pmc=7153464 |doi=10.1097/JCMA.0000000000000270}}</ref><ref name="Wang24Jan2020">{{#invoke:cite journal ||vauthors=Wang C, Horby PW, Hayden FG, Gao GF |title=A novel coronavirus outbreak of global health concern |journal=Lancet |volume=395 |issue=10223 |pages=470–473 |date=February 2020 |pmid=31986257 |pmc=7135038 |doi=10.1016/S0140-6736(20)30185-9 |title-link=doi |doi-access=free}}</ref><ref name="AutoDW-67">{{#invoke:cite journal|| vauthors=Cohen J | date=January 2020|title=Wuhan seafood market may not be source of novel virus spreading globally |url=https://www.science.org/content/article/wuhan-seafood-market-may-not-be-source-novel-virus-spreading-globally|journal=[[Science (journal)|Science]] |doi=10.1126/science.abb0611 |doi-access=free |title-link=doi}}</ref> Official publications from the WHO reported the earliest onset of symptoms as 8{{spaces}}December 2019.<ref>{{#invoke:Cite web||date=12 January 2020|title=Novel Coronavirus – China|website=[[World Health Organization]] (WHO) |url=https://www.who.int/csr/don/12-january-2020-novel-coronavirus-china/en/|url-status=dead|archive-date=14 January 2020|archive-url=https://web.archive.org/web/20200114185815/https://www.who.int/csr/don/12-january-2020-novel-coronavirus-china/en/}}</ref> Human-to-human transmission was confirmed by the WHO and Chinese authorities by 20 January 2020.<ref>{{#invoke:cite news|| vauthors=Kessler G |date=17 April 2020|title=Trump's false claim that the WHO said the coronavirus was 'not communicable' |newspaper=[[The Washington Post]] |url=https://www.washingtonpost.com/politics/2020/04/17/trumps-false-claim-that-who-said-coronavirus-was-not-communicable/|url-status=live |access-date=17 April 2020|archive-date=17 April 2020|archive-url=https://archive.today/20200417193804/https://www.washingtonpost.com/politics/2020/04/17/trumps-false-claim-that-who-said-coronavirus-was-not-communicable/}}</ref><ref>{{#invoke:cite news ||vauthors=Kuo L |date=21 January 2020 |title=China confirms human-to-human transmission of coronavirus |work=[[The Guardian]] |url=https://www.theguardian.com/world/2020/jan/20/coronavirus-spreads-to-beijing-as-china-confirms-new-cases|access-date=18 April 2020}}</ref> According to official Chinese sources, these were mostly linked to the [[Huanan Seafood Wholesale Market]], which also sold live animals.<ref name="characteristicsZH">{{#invoke:cite journal ||title=[The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19) in China] |language=zh |journal=Zhonghua Liu Xing Bing Xue Za Zhi = Zhonghua Liuxingbingxue Zazhi |volume=41 |issue=2 |pages=145–151 |date=February 2020 |pmid=32064853 |doi=10.3760/cma.j.issn.0254-6450.2020.02.003 |s2cid=211133882 |author1=Epidemiology Working Group For Ncip Epidemic Response |author2=Chinese Center for Disease Control Prevention}}</ref> In May 2020, [[George F. Gao|George Gao]], the director of the CDC, said animal samples collected from the seafood market had tested negative for the virus, indicating that the market was the site of an early [[Superspreader|superspreading event]], but that it was not the site of the initial outbreak.<ref>{{#invoke:cite news|| vauthors = Areddy JT |date=26 May 2020|title=China Rules Out Animal Market and Lab as Coronavirus Origin|work=[[The Wall Street Journal]] |url=https://www.wsj.com/articles/china-rules-out-animal-market-and-lab-as-coronavirus-origin-11590517508|access-date=29 May 2020|url-access=subscription}}</ref> Traces of the virus have been found in wastewater samples that were collected in [[Milan]] and [[Turin]], Italy, on 18 December 2019.<ref>{{#invoke:cite news|| vauthors=Kelland K |date=19 June 2020 |title=Italy sewage study suggests COVID-19 was there in December 2019|work=Reuters |url=https://www.reuters.com/article/us-health-coronavirus-italy-sewage/italy-sewage-study-suggests-covid-19-was-there-in-december-2019-idUSKBN23Q1J9|access-date=23 June 2020}}</ref>

By December 2019, the spread of infection was almost entirely driven by human-to-human transmission.<ref name="Epidemiology17Feb2020"/><ref>{{#invoke:cite journal ||vauthors=Heymann DL, Shindo N |title=COVID-19: what is next for public health? |journal=Lancet |volume=395 |issue=10224 |pages=542–545 |date=February 2020 |pmid=32061313 |pmc=7138015 |doi=10.1016/S0140-6736(20)30374-3 |title-link=doi |doi-access=free}}</ref> The number of COVID-19 cases in Hubei gradually increased, reaching sixty by 20 December,<ref>{{#invoke:Cite web|| date=14 March 2020 |vauthors=Bryner J |title=1st known case of coronavirus traced back to November in China |website=livescience.com |url=https://www.livescience.com/first-case-coronavirus-found.html|access-date=31 May 2020}}</ref> and at least 266 by 31 December.<ref>{{#invoke:cite news ||author=Canadian Politics |date=8 April 2020 |title=The birth of a pandemic: How COVID-19 went from Wuhan to Toronto |newspaper=National Post|url=https://nationalpost.com/news/politics/the-birth-of-a-pandemic-how-covid-19-went-from-wuhan-to-toronto |access-date=31 May 2020}}</ref> On 24 December, [[Wuhan Central Hospital]] sent a [[bronchoalveolar lavage fluid]] (BAL) sample from an unresolved clinical case to sequencing company Vision Medicals. On 27 and 28 December, Vision Medicals informed the Wuhan Central Hospital and the Chinese CDC of the results of the test, showing a new coronavirus.<ref>{{#invoke:cite news||author=高昱|date=26 February 2020|title=独家 {{!}} 新冠病毒基因测序溯源: 警报是何时拉响的|language=zh|trans-title=Exclusive {{!}} Tracing the New Coronavirus gene sequencing: when did the alarm sound|work=[[Caixin]]|url=https://china.caixin.com/2020-02-26/101520972.html|access-date=1 March 2020|archive-url=https://web.archive.org/web/20200227094018/https://china.caixin.com/2020-02-26/101520972.html|archive-date=27 February 2020|url-status=dead}}</ref> A pneumonia cluster of unknown cause was observed on 26 December and treated by the doctor [[Zhang Jixian]] in Hubei Provincial Hospital, who informed the Wuhan Jianghan CDC on 27 December.<ref>{{#invoke:Cite web||author1=路子康 |title=最早上报疫情的她, 怎样发现这种不一样的肺炎|website=中国网新闻 |location=北京|language=zh-cn |url=https://news.china.com/zw/news/13000776/20200209/37780703.html |archive-url=https://web.archive.org/web/20200302165302/https://news.china.com/zw/news/13000776/20200209/37780703.html|archive-date=2 March 2020|access-date=11 February 2020}}</ref> On 30 December, a test report addressed to Wuhan Central Hospital, from company CapitalBio Medlab, stated an erroneous positive result for [[SARS]], causing a group of doctors at Wuhan Central Hospital to alert their colleagues and relevant hospital authorities of the result. The Wuhan Municipal Health Commission issued a notice to various medical institutions on "the treatment of pneumonia of unknown cause" that same evening.<ref>{{#invoke:Cite web||title=Undiagnosed pneumonia – China (HU): RFI|url=https://promedmail.org/promed-post/?id=6864153|access-date=7 May 2020|website=ProMED Mail |publisher=ProMED}}</ref> Eight of these doctors, including [[Li Wenliang]] (punished on 3{{spaces}}January),<ref>{{#invoke:cite news||date=7 February 2020|title='Hero who told the truth': Chinese rage over coronavirus death of whistleblower doctor|work=[[The Guardian]]|url=https://www.theguardian.com/global-development/2020/feb/07/coronavirus-chinese-rage-death-whistleblower-doctor-li-wenliang}}</ref> were later admonished by the police for spreading false rumours and another, [[Ai Fen]], was reprimanded by her superiors for raising the alarm.<ref>{{#invoke:cite news ||vauthors=Kuo L |date=11 March 2020 |title=Coronavirus: Wuhan doctor speaks out against authorities |work=The Guardian |location=London|url=https://www.theguardian.com/world/2020/mar/11/coronavirus-wuhan-doctor-ai-fen-speaks-out-against-authorities}}</ref>

The Wuhan Municipal Health Commission made the first public announcement of a pneumonia outbreak of unknown cause on 31 December, confirming 27 cases<ref name="AutoDW-69">{{#invoke:Cite web||title=Novel Coronavirus |url=https://www.who.int/westernpacific/emergencies/novel-coronavirus|access-date=6 February 2020|url-status=live|archive-url=https://web.archive.org/web/20200202151307/https://www.who.int/westernpacific/emergencies/novel-coronavirus|archive-date=2 February 2020|work=[[World Health Organization]] (WHO)}}</ref><ref>{{#invoke:cite news||date=31 December 2019|title=武汉现不明原因肺炎 官方确认属实: 已经做好隔离|publisher=Xinhua Net 新華網 |url=https://news.163.com/19/1231/10/F1NGTJNJ00019K82.html|access-date=31 March 2020}}</ref><ref name="AutoDW-68">{{#invoke:Cite web||date=31 December 2019|script-title=zh:武汉市卫健委关于当前我市肺炎疫情的情况通报 |url=https://wjw.wuhan.gov.cn/front/web/showDetail/2019123108989|url-status=dead|archive-url=https://web.archive.org/web/20200109215413/https://wjw.wuhan.gov.cn/front/web/showDetail/2019123108989|archive-date=9 January 2020 |access-date=8 February 2020|work=WJW.Wuhan.gov.cn|publisher=Wuhan Municipal Health Commission|language=zh}}</ref>{{snd}}enough to trigger an investigation.<ref name="bbc50984025">{{#invoke:cite news||date=3 January 2020|title=Mystery pneumonia virus probed in China|work=[[BBC News]]|url=https://www.bbc.com/news/world-asia-china-50984025|url-status=live|access-date=29 January 2020|archive-url=https://web.archive.org/web/20200105051949/https://www.bbc.com/news/world-asia-china-50984025|archive-date=5 January 2020}}</ref>

During the early stages of the outbreak, the number of cases doubled approximately every seven and a half days.<ref name="Qun29Jan2020">{{#invoke:cite journal || vauthors = Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, Ren R, Leung KS, Lau EH, Wong JY, Xing X, Xiang N, Wu Y, Li C, Chen Q, Li D, Liu T, Zhao J, Liu M, Tu W, Chen C, Jin L, Yang R, Wang Q, Zhou S, Wang R, Liu H, Luo Y, Liu Y, Shao G, Li H, Tao Z, Yang Y, Deng Z, Liu B, Ma Z, Zhang Y, Shi G, Lam TT, Wu JT, Gao GF, Cowling BJ, Yang B, Leung GM, Feng Z  | title = Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia | journal = The New England Journal of Medicine | volume = 382 | issue = 13 | pages = 1199–1207 | date = March 2020 | pmid = 31995857 | pmc = 7121484 | doi = 10.1056/NEJMoa2001316 | title-link = doi | doi-access = free }}</ref> In early and mid-January 2020, the virus spread to other [[Provinces of China|Chinese provinces]], helped by the [[Chunyun|Chinese New Year migration]] and Wuhan being a transport hub and major rail interchange.<ref name="WHOReport24Feb2020" /> On 20 January, China reported nearly 140 new cases in one day, including two people in Beijing and one in [[Shenzhen]].<ref name="france2420200120">{{#invoke:cite news||date=20 January 2020|title=China confirms sharp rise in cases of SARS-like virus across the country|url=https://www.france24.com/en/20200120-china-confirms-sharp-rise-in-cases-of-sars-like-virus-across-the-country|url-status=live|access-date=20 January 2020|archive-url=https://web.archive.org/web/20200120055618/https://www.france24.com/en/20200120-china-confirms-sharp-rise-in-cases-of-sars-like-virus-across-the-country|archive-date=20 January 2020}}</ref> Later official data shows 6,174 people had already developed symptoms by then,<ref name="Epidemiology17Feb2020">{{#invoke:cite journal||vauthors=((The Novel Coronavirus Pneumonia Emergency Response Epidemiology Team)) |date=February 2020|title=The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) – China, 2020 |journal=China CDC Weekly|volume=2|issue=8|pages=113–122|doi=10.46234/ccdcw2020.032 |pmid=34594836|pmc=839292|doi-access=free |title-link=doi}}</ref> and more may have been infected.<ref name="flattery">{{#invoke:cite news||date=25 April 2020|title=Flattery and foot dragging: China's influence over the WHO under scrutiny|work=[[The Globe and Mail]] |url=https://www.theglobeandmail.com/world/article-flattery-and-foot-dragging-chinas-influence-over-the-who-under/}}</ref> A report in ''The Lancet'' on 24 January indicated human transmission, strongly recommended personal protective equipment for health workers, and said testing for the virus was essential due to its "pandemic potential".<ref name="Huang24Jan2020">{{#invoke:cite journal ||vauthors=Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, Zhang L, Fan G, Xu J, Gu X, Cheng Z, Yu T, Xia J, Wei Y, Wu W, Xie X, Yin W, Li H, Liu M, Xiao Y, Gao H, Guo L, Xie J, Wang G, Jiang R, Gao Z, Jin Q, Wang J, Cao B |title=Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China |journal=Lancet |volume=395 |issue=10223 |pages=497–506 |date=February 2020 |pmid=31986264 |pmc=7159299 |doi=10.1016/S0140-6736(20)30183-5 |doi-access=free |title-link=doi}}</ref><ref name="Horton 18 March">{{#invoke:Cite web|| vauthors=Horton R |author-link=Richard Horton (editor)|date=18 March 2020 |title=Scientists have been sounding the alarm on coronavirus for months. Why did Britain fail to act?|url=https://www.theguardian.com/commentisfree/2020/mar/18/coronavirus-uk-expert-advice-wrong |access-date=23 April 2020|website=The Guardian}}</ref> On 30 January, the WHO declared COVID-19 a [[Public Health Emergency of International Concern]].<ref name="flattery" /> By this time, the outbreak spread by a factor of 100 to 200 times.<ref>{{#invoke:Cite web||date=2 June 2020|title=China delayed releasing coronavirus info, frustrating WHO |work=Associated Press |url=https://apnews.com/3c061794970661042b18d5aeaaed9fae|access-date=3 June 2020}}</ref>

Italy had its first confirmed cases on 31 January 2020, two tourists from China.<ref name="Corriere_20Jan">{{#invoke:Cite web||date=31 January 2020|title=Coronavirus: Primi due casi in Italia|trans-title=Coronavirus: First two cases in Italy|url=https://www.corriere.it/cronache/20_gennaio_30/coronavirus-italia-corona-9d6dc436-4343-11ea-bdc8-faf1f56f19b7.shtml|access-date=31 January 2020|work=Corriere della sera|language=it}}</ref> Italy overtook China as the country with the most deaths on 19 March 2020.<ref name="sky11960412">{{#invoke:Cite news||title=Coronavirus: Number of COVID-19 deaths in Italy surpasses China as total reaches 3,405|url=https://news.sky.com/story/coronavirus-number-of-covid-19-deaths-in-italy-surpasses-china-as-total-reaches-3-405-11960412|access-date=7 May 2020|newspaper=Sky News}}</ref> By 26 March the United States had overtaken China and Italy with the highest number of confirmed cases in the world.<ref name="NYT-20200326">{{#invoke:cite news|| vauthors = McNeil Jr DG |author-link=Donald McNeil Jr.|date=26 March 2020|title=The U.S. Now Leads the World in Confirmed Coronavirus Cases|work=The New York Times|url=https://www.nytimes.com/2020/03/26/health/usa-coronavirus-cases.html |archive-url=https://web.archive.org/web/20200326211527/https://www.nytimes.com/2020/03/26/health/usa-coronavirus-cases.html |archive-date=26 March 2020 |url-access=subscription |url-status=live|access-date=27 March 2020}}</ref> Research on coronavirus genomes indicates the majority of COVID-19 cases in [[COVID-19 pandemic in New York (state)|New York]] came from European travellers, rather than directly from China or any other Asian country.<ref name="20200408nytimes">{{#invoke:cite news||date=8 April 2020|title=Studies Show N.Y. Outbreak Originated in Europe|work=The New York Times|url=https://www.nytimes.com/2020/04/08/us/coronavirus-live-updates.html |archive-url=https://web.archive.org/web/20200408185016/https://www.nytimes.com/2020/04/08/us/coronavirus-live-updates.html |archive-date=8 April 2020 |url-access=subscription |url-status=live}}</ref> Retesting of prior samples found a person in France who had the virus on 27 December 2019,<ref name="France-retest">{{#invoke:cite news|| vauthors = Irish J |date=4 May 2020|title=After retesting samples, French hospital discovers COVID-19 case from December|work=[[Reuters]]| veditors = Lough RM, Graff P |url=https://www.reuters.com/article/us-health-coronavirus-france-idUSKBN22G20L|access-date=4 May 2020}}</ref><ref name="Deslandes-2020">{{#invoke:cite journal || vauthors = Deslandes A, Berti V, Tandjaoui-Lambotte Y, Alloui C, Carbonnelle E, Zahar JR, Brichler S, Cohen Y  | title = SARS-CoV-2 was already spreading in France in late December 2019 | journal = International Journal of Antimicrobial Agents | volume = 55 | issue = 6 | pages = 106006 | date = June 2020 | pmid = 32371096 | pmc = 7196402 | doi = 10.1016/j.ijantimicag.2020.106006 }}</ref> and a person in the United States who died from the disease on 6{{spaces}}February 2020.<ref name="PBS-2wks">{{#invoke:Cite web||date=22 April 2020|title=2 died with coronavirus weeks before 1st U.S. virus death|url=https://www.pbs.org/newshour/nation/2-died-with-coronavirus-weeks-before-1st-u-s-virus-death|access-date=23 April 2020|website=PBS NewsHour}}</ref>

RT-PCR testing of untreated wastewater samples from Brazil and Italy have suggested detection of SARS-CoV-2 as early as November and December 2019, respectively, but the methods of such sewage studies have not been optimised, many have not been peer-reviewed, details are often missing, and there is a risk of false positives due to contamination or if only one gene target is detected.<ref>{{#invoke:cite journal || vauthors = Michael-Kordatou I, Karaolia P, Fatta-Kassinos D | title = Sewage analysis as a tool for the COVID-19 pandemic response and management: the urgent need for optimised protocols for SARS-CoV-2 detection and quantification | journal = Journal of Environmental Chemical Engineering | volume = 8 | issue = 5 | pages = 104306 | date = October 2020 | pmid = 32834990 | pmc = 7384408 | doi = 10.1016/j.jece.2020.104306 }}</ref> A September 2020 review journal article said, "The possibility that the COVID‑19 infection had already spread to Europe at the end of last year is now indicated by abundant, even if partially circumstantial, evidence", including pneumonia case numbers and radiology in France and Italy in November and December.<ref name=platto>{{#invoke:cite journal || vauthors = Platto S, Xue T, Carafoli E | title = COVID19: an announced pandemic | journal = Cell Death & Disease | volume = 11 | issue = 9 | pages = 799 | date = September 2020 | pmid = 32973152 | pmc = 7513903 | doi = 10.1038/s41419-020-02995-9 }}</ref>

{{As of|2021|10|1}}, ''[[Reuters]]'' reported that it had estimated the worldwide total number of deaths due to COVID‑19 to have exceeded five million.<ref>{{#invoke:cite news||url=https://www.reuters.com/world/global-covid-19-deaths-hit-5-million-delta-variant-sweeps-world-2021-10-02/|title=Global COVID-19 deaths hit 5 million as Delta variant sweeps the world| vauthors = Kavya B, Abraham R |agency=Reuters| veditors = Shumaker L, Wardell J |date=3 October 2021|work=Reuters.com}}</ref>

The Public Health Emergency of International Concern for COVID-19 ended on May 5, 2023. By this time, everyday life in most countries had returned to how it was before the pandemic.<ref>{{#invoke:cite web||title=From emergency response to long-term COVID-19 disease management: sustaining gains made during the COVID-19 pandemic|url=https://www.who.int/publications/i/item/WHO-WHE-SPP-2023.1|website=www.who.int|publisher=World Health Organization|access-date=9 May 2023|language=en}}</ref><ref>{{#invoke:cite web||date=5 May 2023|title=WHO ends global health emergency declaration for COVID-19|url=https://www.npr.org/sections/goatsandsoda/2023/05/05/1174269442/who-ends-global-health-emergency-declaration-for-covid-19|website=NPR|first1=Giulia|last1=Heyward|first2=Marc|last2=Silver|access-date=9 May 2023}}</ref>