COVID-19 pandemic

=== Background ===
{{Main|Origin of COVID-19|COVID-19 pandemic in Hubei}}
SARS-CoV-2 is a virus closely related to [[Bat virome#Coronaviruses|bat coronaviruses]],<ref name="LancetNowcasting" /> [[pangolin]] coronaviruses,<ref name="ia56U" /><ref name="Zhang6April2020">{{#invoke:cite journal||vauthors=Zhang T, Wu Q, Zhang Z|date=April 2020|title=Probable Pangolin Origin of SARS-CoV-2 Associated with the COVID-19 Outbreak|journal=Current Biology|volume=30|issue=7|pages=1346–1351.e2|doi=10.1016/j.cub.2020.03.022|pmc=7156161|pmid=32197085|bibcode=2020CBio...30E1346Z }}</ref> and [[Severe acute respiratory syndrome coronavirus|SARS-CoV]].<ref name="ECDC risk assessment" /> The first known [[outbreak]] (the [[2019–2020 COVID-19 outbreak in mainland China]]) started in [[Wuhan]], Hubei, China, in December 2019.<ref>{{cite journal |vauthors=Liu J, Liu S, Wei H, Yang X |title=Epidemiology, clinical characteristics of the first cases of COVID-19 |journal=Eur J Clin Invest |volume=50 |issue=10 |pages=e13364 |date=October 2020 |pmid=32725884 |doi=10.1111/eci.13364 |s2cid=220852984 |type=Review}}</ref> Many early cases were linked to people who had visited the [[Huanan Seafood Wholesale Market]] there,<ref name="Sun2020epidemiology">{{#invoke:cite journal || vauthors = Sun J, He WT, Wang L, Lai A, Ji X, Zhai X, Li G, Suchard MA, Tian J, Zhou J, Veit M, Su S | title = COVID-19: Epidemiology, Evolution, and Cross-Disciplinary Perspectives | journal = Trends in Molecular Medicine | volume = 26 | issue = 5 | pages = 483–495 | date = May 2020 | pmid = 32359479 | pmc = 7118693 | doi = 10.1016/j.molmed.2020.02.008 }}</ref><ref>{{#invoke:cite news ||title=WHO Points To Wildlife Farms In Southern China As Likely Source Of Pandemic |url=https://www.npr.org/sections/goatsandsoda/2021/03/15/977527808/who-points-to-wildlife-farms-in-southwest-china-as-likely-source-of-pandemic?t=1616302540855 |publisher=[[NPR]] |date=15 March 2021}}</ref><ref name="Maxmen2021whoReport">{{#invoke:cite journal || vauthors = Maxmen A | title = WHO report into COVID pandemic origins zeroes in on animal markets, not labs | journal = Nature | volume = 592 | issue = 7853 | pages = 173–174 | date = April 2021 | pmid = 33785930 | doi = 10.1038/d41586-021-00865-8 | s2cid = 232429241 | bibcode = 2021Natur.592..173M |doi-access=free}}</ref> but it is possible that human-to-human transmission began earlier.<ref name="Hu2020natureReviews" /><ref name="Graham2020immunity">{{#invoke:cite journal || vauthors = Graham RL, Baric RS | title = SARS-CoV-2: Combating Coronavirus Emergence | journal = Immunity | volume = 52 | issue = 5 | pages = 734–736 | date = May 2020 | pmid = 32392464 | pmc = 7207110 | doi = 10.1016/j.immuni.2020.04.016 }}</ref> [[Molecular clock]] analysis suggests that the first cases were likely to have been between October and November 2019.<ref>{{#invoke:cite journal || vauthors = To KK, Sridhar S, Chiu KH, Hung DL, Li X, Hung IF, Tam AR, Chung TW, Chan JF, Zhang AJ, Cheng VC, Yuen KY | title = Lessons learned 1 year after SARS-CoV-2 emergence leading to COVID-19 pandemic | journal = Emerging Microbes & Infections | volume = 10 | issue = 1 | pages = 507–535 | date = December 2021 | pmid = 33666147 | pmc = 8006950 | doi = 10.1080/22221751.2021.1898291 }}</ref>

The scientific consensus is that the virus is most likely of a [[zoonotic]] origin, from bats or another closely related mammal.<ref name="Hu2020natureReviews">{{#invoke:cite journal || vauthors = Hu B, Guo H, Zhou P, Shi ZL | title = Characteristics of SARS-CoV-2 and COVID-19 | journal = Nature Reviews. Microbiology | volume = 19 | issue = 3 | pages = 141–154 | date = March 2021 | pmid = 33024307 | pmc = 7537588 | doi = 10.1038/s41579-020-00459-7 }}</ref><ref>Multiple sources:
* {{#invoke:cite news ||work=[[EurekAlert!]] |publisher=Scripps Research Institute |title=The COVID-19 coronavirus epidemic has a natural origin, scientists say – Scripps Research's analysis of public genome sequence data from SARS‑CoV‑2 and related viruses found no evidence that the virus was made in a laboratory or otherwise engineered |url=https://www.eurekalert.org/pub_releases/2020-03/sri-tcc031720.php |date=17 March 2020 |access-date=15 April 2020 }}
* {{#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 | doi-access = free }}
* {{#invoke:cite journal || vauthors = Latinne A, Hu B, Olival KJ, Zhu G, Zhang L, Li H, Chmura AA, Field HE, Zambrana-Torrelio C, Epstein JH, Li B, Zhang W, Wang LF, Shi ZL, Daszak P | title = Origin and cross-species transmission of bat coronaviruses in China | journal = Nature Communications | volume = 11 | issue = 1 | page = 4235 | date = August 2020 | pmid = 32843626 | pmc = 7447761 | doi = 10.1038/s41467-020-17687-3 | bibcode = 2020NatCo..11.4235L }}
* {{#invoke:cite news || vauthors = Fox M |date=7 July 2021 |title=Coronavirus almost certainly came from an animal, not a lab leak, top scientists argue |url=https://www.cnn.com/2021/07/07/health/origins-coronavirus-letter-virologists-scn/index.html |work=CNN |location= |access-date=9 July 2021}}
* {{#invoke:cite news ||author=<!--Staff writer(s)/no by-line.--> |date=19 November 2021 |title=Market in China's Wuhan likely origin of COVID-19 outbreak – study |url=https://www.reuters.com/world/market-chinas-wuhan-likely-origin-covid-19-outbreak-study-2021-11-19/ |work=Reuters |location= |access-date=19 November 2021}}</ref><ref name="To2021lessons">{{#invoke:cite journal||vauthors=To KK, Sridhar S, Chiu KH, Hung DL, Li X, Hung IF, Tam AR, Chung TW, Chan JF, Zhang AJ, Cheng VC, Yuen KY|date=March 2021|title=Lessons learned 1 year after SARS-CoV-2 emergence leading to COVID-19 pandemic|journal=Emerging Microbes & Infections|volume=10|issue=1|pages=507–535|doi=10.1080/22221751.2021.1898291|pmc=8006950|pmid=33666147}}</ref> While other explanations such as speculations that SARS-CoV-2 was accidentally [[COVID-19 lab leak theory|released from a laboratory]] have been proposed,<ref name="CovidMayHave">{{cite news |last1=Horowitz |first1=Josh |last2=Stanway |first2=David |date=9 February 2021 |title=COVID may have taken 'convoluted path' to Wuhan, WHO team leader says |publisher=Reuters |url=https://www.reuters.com/article/us-health-coronavirus-who-china/covid-may-have-taken-convoluted-path-to-wuhan-who-team-leader-says-idUSKBN2A90BW |url-status=live |access-date=10 February 2021 |archive-url=https://web.archive.org/web/20210210092128/https://www.reuters.com/article/us-health-coronavirus-who-china/covid-may-have-taken-convoluted-path-to-wuhan-who-team-leader-says-idUSKBN2A90BW |archive-date=10 February 2021}}</ref><ref name="nofact">{{cite news |last1=Pauls |first1=Karen |last2=Yates |first2=Jeff |date=27 January 2020 |title=Online claims that Chinese scientists stole coronavirus from Winnipeg lab have 'no factual basis' |publisher=Canadian Broadcasting Corporation |url=https://www.cbc.ca/news/canada/manitoba/china-coronavirus-online-chatter-conspiracy-1.5442376 |url-status=live |access-date=8 February 2020 |archive-url=https://web.archive.org/web/20200208134329/https://www.cbc.ca/news/canada/manitoba/china-coronavirus-online-chatter-conspiracy-1.5442376 |archive-date=8 February 2020}}</ref><ref name="20200208economist">{{cite news |date=8 February 2020 |title=China's rulers see the coronavirus as a chance to tighten their grip |newspaper=[[The Economist]] |url=https://www.economist.com/china/2020/02/08/chinas-rulers-see-the-coronavirus-as-a-chance-to-tighten-their-grip |url-status=live |access-date=29 February 2020 |archive-url=https://archive.today/20200229034330/https://www.economist.com/china/2020/02/08/chinas-rulers-see-the-coronavirus-as-a-chance-to-tighten-their-grip |archive-date=29 February 2020}}</ref> these are not supported by evidence.<ref name="Holmes2021">{{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 |title=The Origins of SARS-CoV-2: A Critical Review |journal=Cell |date=August 2021 | volume = 184 | issue = 19 | pages = 4848–4856 |doi=10.1016/j.cell.2021.08.017| pmid = 34480864 |pmc=8373617 }}</ref>