COVID-19 pandemic

=== 2019 ===
{{Main|Timeline of the COVID-19 pandemic in 2019}}
The [[outbreak]] was discovered in Wuhan in November 2019. It is possible that human-to-human transmission was happening before the discovery.<ref name="Hu2020natureReviews" /><ref name="Graham2020immunity" /> 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.<ref name="original_report" />

A [[pneumonia]] cluster was observed on 26 December and treated by Chinese pulmonologist [[Zhang Jixian]]. She informed the Wuhan Jianghan CDC on 27 December.<ref name="D54YB">{{#invoke:cite web||last1=Lu|first1=Zikang (路子康)|script-title=zh:最早上报疫情的她，怎样发现这种不一样的肺炎|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|location=Beijing|language=zh-cn|script-website=zh:中国网新闻}}</ref> After analyzing pneumonia patient samples, a genetic sequencing company named Vision Medicals reported the discovery of a [[novel coronavirus]] to the [[Chinese Center for Disease Control and Prevention|China CDC]] (CCDC) on 28 December.<ref name="AP OR">{{#invoke:cite news|| url=https://apnews.com/article/3c061794970661042b18d5aeaaed9fae|title=China delayed releasing coronavirus info, frustrating WHO|date=2 June 2020|work=Associated Press|access-date=26 October 2021|archive-url=https://web.archive.org/web/20211025163939/https://apnews.com/article/united-nations-health-ap-top-news-virus-outbreak-public-health-3c061794970661042b18d5aeaaed9fae |archive-date=25 October 2021 |url-status=live}}</ref><ref name="caixintrace">{{#invoke:cite news ||last1=Gao |first1=Yu (高昱) |script-title=zh:独家 {{!}} 新冠病毒基因测序溯源：警报是何时拉响的|trans-title=Exclusive {{!}} Tracing the New Coronavirus gene sequencing: when did the alarm sound|work=[[Caixin]]|date=26 February 2020|language=zh|url=https://china.caixin.com/2020-02-26/101520972.html|archive-url=https://web.archive.org/web/20200227094018/https://china.caixin.com/2020-02-26/101520972.html|archive-date=27 February 2020|access-date=1 March 2020|url-status=dead}}</ref>

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 3 January), were later admonished by the police for spreading false rumours. Director of the Emergency Department at the Central Hospital of Wuhan, Ai Fen, was also reprimanded.<ref name="siStf" /><ref name="20200311theguardian">{{#invoke:cite news ||url=https://www.theguardian.com/world/2020/mar/11/coronavirus-wuhan-doctor-ai-fen-speaks-out-against-authorities |title=Coronavirus: Wuhan doctor speaks out against authorities | vauthors = Kuo L |work=The Guardian |location=London |date=11 March 2020 }}</ref> That evening, Wuhan Municipal Health Commission (WMHC) issued a notice about "the treatment of pneumonia of unknown cause".<ref name="promedmail6864153">{{#invoke:cite news || title=Undiagnosed pneumonia – China (HU): RFI |url=https://promedmail.org/promed-post/?id=6864153 |newspaper=Promed-Mail |publisher=ProMED |date=30 December 2019|access-date=7 May 2020}}</ref> The next day, WMHC made the announcement public, confirming 27 cases<ref name="AutoDW-69" /><ref name="AutoDW-68" />—enough to trigger an investigation.<ref name="bbc50984025" />

On 31 December, the WHO office in China was notified about the cluster of unknown pneumonia cases<ref name="WHO report">{{#invoke:cite web || title=Novel Coronavirus (2019-nCoV) SITUATION REPORT – 1 |url=https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200121-sitrep-1-2019-ncov.pdf |publisher=World Health Organization |access-date=7 June 2021 |date=20 January 2020}}</ref><ref name="AutoDW-69" /> and immediately launched an investigation.<ref name="bbc50984025" />

Official Chinese sources claimed that the early cases were mostly linked to the Huanan Seafood Wholesale Market, which also sold live animals.<ref name="characteristicsZH" /> In May 2020, CCDC director George Gao initially ruled out the market as a possible origin, as animal samples collected there had tested negative.<ref name="ALmAQ">{{#invoke:cite news ||url=https://www.wsj.com/articles/china-rules-out-animal-market-and-lab-as-coronavirus-origin-11590517508 |title=China Rules Out Animal Market and Lab as Coronavirus Origin | vauthors = Areddy JT |date=26 May 2020 |access-date=29 May 2020 |work=The Wall Street Journal}}</ref>