In Congress, multiple bills and resolutions have been introduced related to China's handling of a novel coronavirus outbreak in Wuhan, China, that expanded to become the coronavirus disease 2019 (COVID-19) global pandemic. This report provides a timeline of key developments in the early weeks of the pandemic, based on available public reporting to date. The timeline starts with the onset of symptoms among the first known patients later identified as having COVID-19. The timeline documents the subsequent responses in China, at the World Health Organization (WHO), and in the United States through January 31, 2020, the day U.S. Department of Health and Human Services (HHS) Secretary Alex M. Azar II declared the pandemic had become a public health emergency for the United States. The report opens with short sections on disease terminology and the Chinese geographic and political context of the outbreak in its early weeks. The report next offers discussion of select issues raised by the timeline. A detailed timeline follows. A concise timeline is included in an Appendix . On February 11, 2020, the International Committee on Taxonomy of Viruses named the novel coronavirus "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2). The name references the virus' genetic link to the coronavirus responsible for the 2002-2003 severe acute respiratory syndrome (SARS) outbreak, which began in China's Guangdong Province and sparked global panic, infecting 8,096 people worldwide and causing 774 deaths. Also on February 11, WHO named the disease caused by SARS-CoV-2 "coronavirus disease 2019" (COVID-19). Earlier, from January 30, 2020, to February 11, WHO referred to the virus by the interim name "2019 novel coronavirus" (2019 nCoV), and to the disease by the interim name, "2019 novel coronavirus acute respiratory disease" (2019-nCoV acute respiratory disease). China initially referred to the illness its doctors were observing in Wuhan as "pneumonia of unknown cause." Beginning on January 1, 2020, official Chinese sources began referring to it as a "viral pneumonia." On January 12, 2020, the day after China shared the genomic sequence of the novel coronavirus with WHO and on an open-source platform, Wuhan authorities began using the term, "novel coronavirus infection pneumonia." The government and media in China continue to refer to the disease by that name. Chinese doctors first identified cases of the disease later named COVID-19 in Wuhan, capital of China's Hubei Province. Wuhan, with a population of 11.2 million, is the largest city in central China, a region comprised of six provinces with a combined population of 368 million. Situated at the intersection of the Yangtze River and its largest tributary, the Hanshui River, the city is a major transportation hub, with river, highway, high-speed rail, and air links to the rest of China. Until the pandemic led airlines to suspend service, the city also offered direct air routes to destinations around the world. Wuhan is a major industrial base and boasts a concentration of elite universities and research centers. The Wuhan Municipal Health Commission, the city's health agency, is in the third tier of a national health hierarchy that extends from the National Health Commission in Beijing down through the Health Commission of Hubei Province, whose offices are also located in Wuhan. The Wuhan Municipal Health Commission reports both to the Wuhan People's Government and to the provincial health commission. The Wuhan Municipal Health Commission directly oversees a dozen hospitals and the Wuhan Center for Disease Control and Prevention (Wuhan CDC), which has a staff of about 220. Wuhan is divided into 13 districts. Each has its own health bureau and CDC, which report both to the district government and the next higher-level entity in their hierarchies, the Wuhan Municipal Health Commission and Wuhan CDC. Jianghan District, home to the Huanan Seafood Wholesale Market, where a number of earliest known COVID-19 patients worked, has a population of 730,000. Population density in Jianghan District is on par with Manhattan. In China's political system, Communist Party secretaries are the most powerful officials at every level of government. They oversee the party bureaucracy and make major decisions. A deputy party secretary usually serves concurrently as head of the parallel state bureaucracy, which implements the Party's decisions. At the national level, Communist Party General Secretary Xi Jinping is China's top leader. He serves concurrently as Chairman of the Party's Central Military Commission and as State President. The Party's second-most senior official, Li Keqiang, serves as Premier of the State Council, or cabinet, overseeing China's state bureaucracy. Both men are members of China's most senior decisionmaking body, the seven-man Communist Party Politburo (or Political Bureau) Standing Committee. At the outset of the epidemic, the top officials of Hubei Province were Party Secretary Jiang Chaoliang and Governor Wang Xiaodong, with the latter serving concurrently as a provincial deputy party secretary. The Party removed Jiang from office on February 13, 2020, and replaced him with former Shanghai Mayor Ying Yong, an associate of Party General Secretary Xi. Governor Wang remains in office. In the city of Wuhan, the top officials at the outset of the epidemic were Party Secretary Ma Guoqiang, who served concurrently as a deputy party secretary for Hubei Province, and Mayor Zhou Xianwang, who served concurrently as the city's deputy party secretary. The Party removed Ma from his provincial and municipal party posts on February 13, 2020, and replaced him with the former Party Secretary of the eastern China city of Jinan, Wang Zhonglin. Mayor Zhou remains in office. At the outset of the epidemic, the top officials of the Hubei Provincial Health Commission were Party Secretary Zhang Jin and Director Liu Yingzi. The Party removed both from their posts on February 11, 2020, replacing them with a former deputy director of China's National Health Commission, Wang Hesheng. The top official of the Wuhan Municipal Health Commission remains Zhang Hongxing. He has served as both Party Secretary and Director of the commission since early 2019. In 2002-2003, China's government was widely criticized for waiting more than two months to report the outbreak of SARS to WHO and to its own people. China has shared information about COVID-19 more quickly and comprehensively. The timeline shows, for example, that Chinese authorities allowed experts from the WHO China Country Office and WHO's Western Pacific Regional Office to conduct what WHO describes as "a brief visit to Wuhan" January 20-21, 2020. The timeline nonetheless raises questions for some about China's interactions with WHO at key moments in the early weeks of the pandemic. Article 6 of the International Health Regulations (IHR) (2005), an international agreement to which China, the United States, and 194 other countries are parties, outlines State Parties' obligations, including: Each State Party shall assess events occurring within its territory.... Each State Party shall notify WHO, by the most efficient means of communication available, by way of the National IHR Focal Point, and within 24 hours of assessment of public health information, of all events which may constitute a public health emergency of international concern within its territory.... Following a notification, a State Party shall continue to communicate to WHO timely, accurate and sufficiently detailed public health information available to it on the notified event, where possible including case definitions, laboratory results, source and type of the risk, number of cases and deaths, conditions affecting the spread of the disease and the health measures employed; and report, when necessary, the difficulties faced and support needed in responding to the potential public health emergency of international concern. The timeline suggests that in the early weeks of the pandemic, Chinese authorities may not always have communicated with WHO in the "timely, accurate and sufficiently detailed" way IHR (2005) requires. It appears China may not have proactively notified WHO of the outbreak, as required by Article 6.1 of IHR (2005). According to Dr. Michael Ryan, Executive Director of WHO's Health Emergencies Programme, WHO headquarters in Geneva first learned about the outbreak in Wuhan not directly from Chinese authorities, but rather from the Program for Monitoring Emerging Diseases (ProMED), a U.S.-based open-source platform for early intelligence about infectious disease outbreaks. At 11:59 p.m. Eastern Standard Time (EST), a ProMed user posted a machine translation of a Chinese-language report about the outbreak from a news organization, Yicai , the financial news arm of China's state-owned Shanghai Media Group. Yicai had published its report online just under three hours earlier. It detailed the contents of two Wuhan Municipal Health Commission "urgent notices" about atypical pneumonia cases, which the commission had sent the day before to medical institutions in Wuhan, and which internet users in Wuhan had leaked online within minutes. Another document from Wuhan that circulated widely online overnight on December 30-31âa photograph of a patient lab report showing a positive result for SARS, with the SARS finding circled in redâalerted Chinese news organizations to the possible significance of the "urgent notices." The head of emergency medicine at Wuhan Central Hospital, Dr. Ai Fen, had shared the image online with a former classmate and a group of colleagues in the time between the issuance of the two Wuhan Municipal Health Commission "urgent notices" on December 30. Another Wuhan Central Hospital doctor, Li Wenliang, had shared the image with a group of his former classmates in a private online WeChat group a few hours later. (Dr. Li would later be reprimanded by Wuhan authorities for his social media posts, celebrated by the Chinese public as a whistleblower, and fall victim to COVID-19. He died on February 7, 2020, at the age of 33. ) For WHO, the ProMED post appears to have triggered Articles 9 and 10 of IHR (2005). Article 9 provides for WHO to "take into account reports from sources other than notifications or consultations" by State Parties, and then "attempt to obtain verification from the State Party in whose territory the event is allegedly occurring." Article 10 requires State Parties to respond to verification requests from WHO within 24 hours. Speaking at a WHO press conference on April 20, 2020, Ryan said as soon as WHO headquarters learned about the outbreak from ProMed on December 31, it asked the WHO China Country Office to request "verification of the event" from the government of China under IHR (2005). Ryan noted, "member states are required to respond within 24 to 48 hours of any request from the WHO for clarification or verification of an event or a signal that we believe may be significant." (IHR (2005) stipulates 24 hours, not 48.) China's official timeline says it began "regularly informing" WHO of developments related to the outbreak on January 3. On January 4, WHO tweeted, "China has reported to WHO a cluster of pneumonia casesâwith no deathsâin Wuhan, Hubei Province." WHO's Ryan said the WHO China Country Office formally requested verification of the outbreak on January 1, "[t]hat process continued and on 4 th January WHO tweeted the existence of the event." Whether intentionally or otherwise, WHO's first formal statement about the outbreak, on January 5, was not clear on how the WHO Country Office learned about the outbreak. It used passive voice to state that the China Country Office "was informed" on December 31, 2019, of cases of pneumonia of unknown cause in Wuhan. China's government appears to have potentially hesitated before informing WHO both when it determined a novel coronavirus was responsible for the outbreak and when its scientists sequenced the virus' genome. On January 9, 2020, WHO announced, "Chinese authorities have made a preliminary determination of a novel (or new) coronavirus, identified in a hospitalized person with pneumonia in Wuhan." On January 11, 2020, WHO tweeted, "BREAKING: WHO has received the genetic sequences for the novel #coronavirus (2019-nCoV) from the Chinese authorities." China appears to have determined that a novel coronavirus was responsible days before January 9, 2020, however. Its scientists also sequenced the virus' genome days earlier than January 11, 2020. According to Caixin , a respected Chinese news organization, hospitals in Wuhan sent samples from their pneumonia cases to commercial companies for analysis in late December 2019. Several of those companies informed the hospitals that the patient samples indicated a novel coronavirus. One company, BGI Genomics, completed genomic sequencing of the novel coronavirus on December 26, 2019, Caixin reports. The next entity reported to have sequenced the genome was the Wuhan Institute of Virology (WIV), an affiliate of the Chinese Academy of Sciences. Chinese state media say WIV sequenced the virus' genome on January 2. A timeline in a March 26, 2020, article by China CDC experts and others in T he New England Journal of Medicine indicates China CDC sequenced the genome on January 3, 2020. China's official timelines provide January 7 as the date China CDC sequenced the genome. January 9, 2020, media reports about the CDC's sequencing breakthrough appear to have prompted WHO to issue its statement announcing identification of a novel coronavirus. A fourth group of scientists, led by Prof. Yong-zhen Zhang of Fudan University in Shanghai, sequenced the genome on January 5, 2020, and was the first to share it with the world. They deposited the sequence with the U.S. National Institutes of Health's GenBank, a database of publicly available DNA sequences, on January 5, submitted a paper on their work to the journal Nature on January 7, 2020, and posted the genome on Virological.org, an open-access hub for pre-publication data and analyses, on the morning of January 11. Later on January 11, 2020, a team from China CDC and two other teams shared genomic sequences of the novel coronavirus on Global Initiative on Sharing All Influenza Data (GISAID), an international platform for sharing influenza data, and WHO tweeted that Chinese authorities had provided WHO with genetic sequences for the virus. Chinese authorities do not appear to have shared biological samples with WHO or other international partners as of January 28, 2020, and possibly as of April 25. A line in a January 28, 2020, WHO press release about WHO Director-General Dr. Tedros Adhanom Ghebreyesus' meeting with Chinese leader Xi Jinping indicates that China's government had yet to share biological samples with the organization. Among other things, Director-General Tedros and Xi discussed, "continuing to share data, and for China to share biological material with WHO," the WHO press release stated. On April 25, 2020, State Department Spokesperson Morgan Ortagus tweeted, "China has not shared any #COVID19 virus or clinical samples to the best of our knowledge." The timeline indicates that information Chinese authorities provided to the Chinese public and to the world in the early weeks of the epidemic was often incomplete and understated the extent of the virus' spread. China shared more information beginning January 20, 2020. On January 21, for example, China's National Health Commission began issuing daily updates on case numbers. Information gaps in the early weeks and other information-sharing issues include the following. Wuhan doctors suspected person-to-person transmission of the mysterious new pneumonia as early as late December. Dr. Zhang Jixian of the Hubei Provincial Hospital of Integrated Chinese and Western Medicine later told China's state news agency that she reported a family cluster of cases to her superiors on December 27, 2019, because, "It is unlikely that all three members of a family caught the same disease at the same time unless it is an infectious disease." When visitors from Hong Kong, Macao, and Taiwan visited Wuhan January 13-14, 2020, an official from China's National Health Commission told them, "limited human-to-human transmission cannot be excluded." A WHO expert echoed that position in a January 14, 2020, press conference, stating that China had experienced "limited" human-to-human transmission of the novel coronavirus, mainly in families. Chinese authorities first publicly confirmed person-to-person transmission on January 20. Wuhan medical personnel began falling ill with symptoms similar to their patients' in December, but Chinese authorities did not acknowledge medical worker infections until January 20. The best-known victim of the novel coronavirus in China is Dr. Li Wenliang of Wuhan Central Hospital, whom Wuhan police reprimanded on January 3, 2020, for sharing information about the virus online. Li was hospitalized on January 12, 2020, and died on February 7, 2020. Among other reports of medical worker infections, a single "super-spreader" patient who underwent surgery at the Wuhan Union Hospital on January 7, 2020, was later found to have infected 14 medical staff. Wuhan's Municipal Health Commission issued no updates while a five-day-long political meeting took place in the city January 6-10. For the duration of a second major political meeting in the city, January 12-17, the Wuhan Municipal Health Commission issued daily updates, but reported no new infections. The commission's report on January 11, issued on the day between the two political meetings, gave the impression the epidemic was shrinking. On January 5, the commission had reported a cumulative 59 cases in the city. On January 11, it revised the cumulative number of cases down to 41, a number that remained constant through January 16. The absence of updates from January 6 to 10, and the official statements that no new cases had been detected between January 3 and January 16, may have given Wuhan residents a false sense of security that the outbreak was under control. The United States made multiple offers over the course of January 2020 to send a U.S. Centers for Disease Control and Prevention (U.S. CDC) team to China to assist with response to the outbreak. Any team that went would also have learned information about the epidemic of relevance to the U.S. response. The timeline shows U.S. officials offered to send a U.S. CDC team on January 4, January 6, and January 27. On January 27, President Trump supported the offer with a tweet, saying, "We have offered China and President Xi any help that is necessary. Our experts are extraordinary!" No U.S. CDC team traveled to China in this period, although Weigong Zhou, an employee of U.S. CDC, and Clifford Lane, an employee of the U.S. National Institutes of Health (NIH), did participate in a WHO-China Joint Mission to China from February 16 to 24, 2020. Although Chinese experts have published a stream of papers in English-language scientific journals since the epidemic began, including several important papers in January 2020, some in the international community have expressed frustration over what China has not shared. One area of interest is analysis of samples from the Huanan Seafood Wholesale Market (also referred to in some sources as South China Seafood City). China CDC provided summary details of its findings to Chinese state mediaâit found 33 of 585 samples tested positive for SARS-Cov-2âbut China CDC has not issued details of its scientific analysis of the samples and appears to have not taken samples from animals in the market. Chinese media reports indicate that local authorities disinfected the market on at least the two nights before it closed, potentially also compromising samples. On May 6, 2020, Secretary of State Michael R. Pompeo stated, "China is still refusing to share the information we need to keep people safe, such as viral isolates, clinical specimens, and details about the many COVID-19 patients in December 2019, not to mention 'patient zero.'" It remains unclear who was responsible for decisions to withhold information in the early weeks. In a nationally televised interview, Wuhan Mayor Zhou Xianwang pointed to China's Law on Prevention and Control of Infectious Diseases , which he said restricted Wuhan from sharing information without permission from higher-ups. In addition to examples of incomplete information provided by Chinese authorities, the timeline of events through January 31, 2020, includes instances of official actions to discipline those who shared information about the epidemic publicly, as well as examples of censorship. They include the following: Wuhan Municipal Public Security officers reprimanded at least eight people for allegedly "spreading rumors" about the outbreak and thereby creating a "negative social influence." It remains unclear whether two of the best known medical workers reprimanded for sharing early information about the outbreak, Wuhan Central Hospital's Dr. Ai Fen and Dr. Li Wenliang, are counted among the eight, or if theirs are additional cases. The day after the team of scientists led by Prof. Yong-zhen Zhang of Fudan University in Shanghai became the first to share the genetic sequence of the novel coronavirus with the world, Shanghai authorities closed down Professor Zhang's laboratory for "rectification," implying it is being investigated for unspecified wrongdoing. Hong Kong's South Morning Post , which reported the development, wrote that it was "not clear whether the closure was related to the publishing of the sequencing data before the authorities." Official Chinese timelines omit mention of the team's work. Official censorship has blocked access to enterprising reporting undertaken by both Chinese and foreign news organizations. Dr. Ai Fen's first-person account in a national magazine, People ( Renwu ), for example, was deleted from Renwu's website the day it appeared, though Chinese internet users have worked to keep it accessible. Chinese activists have archived it and many other censored reports on sites such as Terminus2049. Some of those activists are now missing. Prior to January 20, the public record provides little evidence that China's top leaders saw containment of the epidemic as a high priority. China's state media reported three meetings of China's top decisionmaking body, the seven-man Communist Party Politburo (also known as "Political Bureau") Standing Committee, in the month of January 2020, on January 7, 13, and 25. Contemporaneous reporting on the first two meetings made no mention of the epidemic, although on February 15 the Communist Party released February 3 remarks in which General Secretary Xi recalled having "raised a demand for prevention and control of the novel coronavirus pneumonia" at the January 7 meeting. People's Daily , the newspaper of the Communist Party Central Committee, made no mention of the epidemic in its pages until January 21, when it carried six articles, including two on the front page. Chinese officials at all levels monitored the paper closely for signals about leadership priorities. General Secretary Xi, in his capacity as State President, made an official visit to Burma from January 17-18, 2020, to celebrate the 70 th anniversary of bilateral diplomatic relations. State media coverage of the trip gave no indication that Xi and his Burmese hosts discussed the epidemic or efforts by China to contain it. The Chinese leadership's approach to the epidemic changed dramatically on January 20. On that day, a medical expert lauded for his role in the SARS epidemic, Zhong Nanshan, officially confirmed human-to-human transmission and medical worker infections. China's National Health Commission declared novel coronavirus-caused pneumonia a statutory notifiable infectious disease under the PRC Law on the Prevention and Treatment of Infectious Diseases . China also amended the PRC Health and Quarantine Law , opening the way for mandatory quarantines and lock-downs. The day ended with General Secretary Xi issuing an "important instruction," carried in all major media, to prioritize novel coronavirus prevention and control work. China's holiday calendar likely set back efforts to contain the outbreak and contributed to its spread overseas. The Lunar New Year, also known as Spring Festival, is China's most important holiday. In 2020, it fell on January 25. Ahead of the holiday, millions of Wuhan residents left the city to return to their hometowns to spend the festival with their extended families. A smaller number of Wuhan residents got on planes to holiday destinations abroad. In Wuhan, a community of 40,000 households with a two-decade tradition of mass potluck banquets ahead of the Lunar New Year went ahead with its 20 th annual potluck on January 18, 2020, contributing to the virus' spread. Note that when times are listed, the timeline also notes the time zone, whether Chinese Standard Time (CST) for China, Eastern Standard Time (EST) for the eastern part of the contiguous United States, or Central European Time (CET) for Geneva, Switzerland, the headquarters location for WHO. Retrospectively, the date the earliest known COVID-19 patient first developed symptoms remains unclear. In a March 2020 report, the Hong Kong-based South China Morning Post , citing Chinese "government data seen by the Post ," indicates that the first known patient was a 55-year-old from Hubei Province who became ill on November 17. Asked in March 2020 about the Post report, China CDC Director Gao Fu states, "There is no solid evidence to say we already had clusters in November." In a January 24, 2020, article in The Lancet medical journal, doctors from a Wuhan infectious disease hospital and their co-authors state that among the first 41 cases in Wuhan later identified as being COVID-19, the first patient showed symptoms on December 1. In January 11-12 communications with WHO and in an authoritative February 17 report, Chinese authorities provide December 8 as the day when the first known patient later identified as having COVID-19 became symptomatic. Doctors at Wuhan Central Hospital take fluid samples from the lungs of a 65-year-old patient with pneumonia and send them to Vision Medicals, a genomics company in Guangzhou, Guangdong Province, for testing. Another Wuhan hospital sends a sample from a pneumonia patient to publicly-listed genomics company BGI Genomics for analysis. Dr. Zhang Jixian, Director of Respiratory and Critical Care Medicine at the Hubei Provincial Hospital of Integrated Chinese and Western Medicine in Wuhan, files a report with her supervisors about three members of a single family whom she found to be suffering from pneumonia of unknown cause. She later recalls concluding, "It is unlikely that all three members of a family caught the same disease at the same time unless it is an infectious disease." The hospital notifies Center for Disease Control for its district of Wuhan, Jianghan District. Vision Medicals, the genomics company to which Wuhan Central Hospital sent samples from the lungs of the 65-year-old patient for analysis on December 24, calls with the results. According to an account Dr. Zhao Su, the hospital's head of respiratory medicine, gave news organization Caixin in February 2020, "They just called us and said it was a new coronavirus." Wuhan Central Hospital admits a 41-year-old man with pneumonia, collects biological samples from him, and sends the swabs to another laboratory, CapitalBio Medlab Co. Ltd., for analysis. The Hubei Provincial Hospital of Integrated Chinese and Western Medicine has identified additional cases of pneumonia of unknown cause. Other hospitals in Wuhan are reporting similar cases. Wuhan Municipal CDC organizes an expert team to investigate. BGI Genomics is the first known entity to complete sequencing of the novel coronavirus virus, based on the sample sent to it on December 26. A BGI Genomics source later tells Caixin the company did not know the virus was responsible for multiple illnesses and so did not understand the significance of its work at the time. 3:10 p . m . (CST) : The Wuhan Municipal Health Commission issues an "urgent notice" intended only for medical institutions in Wuhan. It states that cases of pneumonia of unknown cause have emerged from the city's Huanan Seafood Wholesale Market. It orders hospitals to compile statistics on all such cases admitted in the previous week and report them by email to the Health Commission by 4 p.m. A later investigation by the National State Supervisory Commission, an agency tasked with investigating graft and malfeasance among public servants, will reveal that someone leaks the notice online within 12 minutes of its being issued. About 12 p.m. CST : Dr. Ai Fen, head of the emergency department at Wuhan Central Hospital, receives a WeChat message from a former classmate at another hospital, Tongji Hospital, asking about a message circulating online: "Don't go to Huanan [Market]. A lot of people there have feversâ¦." Dr. Ai sees the message from her classmate while she is reviewing a computed tomography (CT) scan of an infected patient's lungs. She records an 11-second clip of the CT scan and sends it to him. A bout 4 p.m . CST : Dr. Ai Fen reads Capital Bio's laboratory report on the patient admitted on December 27, which states that his sample has tested positive for Severe Acute Respiratory Disease (SARS). (The finding is later determined to be erroneous. The patient was infected with the novel coronavirus, later named SARS-CoV-2.) Dr. Ai telephones the hospital's public health department and its infectious disease department to report the finding and tells the director of the respiratory disease department in person. Then she draws a red line around the "SARS" finding and shares an image of the report online with her classmate at Tongji Hospital, as well as with a group of colleagues. She will later say she does so "to remind everyone to pay attention to protecting themselves." 5:43 p . m . CST : Wuhan Central Hospital ophthalmologist Li Wenliang sends a message to a group of his medical school classmates on the WeChat social media platform, reporting, "7 confirmed SARS cases from the Huanan Fruit and Seafood Market." Dr. Li does not personally know Dr. Ai Fen, but he sends an image of the laboratory report Dr. Ai shared with her associates less than two hours earlier. He also sends the 11-second lung CT scan of a patient's lungs that Dr. Ai shared with her classmate at noon. 6:50 p . m . CST : The Wuhan Municipal Health Commission issues a second "urgent notice" to medical institutions, instructing them on how to manage patients with pneumonia of unknown cause and ordering them to track such cases and report them in a timely fashion to district CDCs and the Wuhan Municipal Health Commission. A later investigation by China's State Supervisory Commission will reveal that someone leaks the notice online within 10 minutes of its being issued. The Wuhan Municipal Health Commission alerts China's National Health Commission and China CDC in Beijing to the cases. The National Health Commission dispatches a working group and the first of several expert teams to Wuhan. Morning CST: Several Chinese media outlets confirm the authenticity of the Wuhan Health Commission's "urgent notices" of the day before, which spread rapidly across social media overnight. Yicai (also known as China Business News ), the financial news arm of state-owned Shanghai Media Group, confirms the notices are genuine by calling the Wuhan Municipal Health Commission's public hotline number. Yicai publishes a story on the outbreak in Wuhan online at 10:16 a.m. CST. Another Chinese news organization, Xin Jing Bao , confirms the authenticity of the documents with Wuhan CDC, and publishes its own story 37 minutes later. 11:59 p.m. EST ( December 30 ) / 5:59 a.m. CET (Geneva)/12:59 p.m. CST ) : A user of the U.S.-based listserv Program for Monitoring Emerging Diseases or ProMED posts a machine translation of Yicai's article. 1:38 p . m . CST : The Wuhan Municipal Health Commission posts on its website its first public statement on the outbreak. It states that some medical institutions in the city have treated cases of pneumonia linked to the city's Huanan Seafood Wholesale Market. The commission says it asked medical institutions to search for cases related to the market and do retrospective investigations, and they identified 27 cases, including seven cases in which patients are seriously ill. The commission notes that hygiene investigation and environmental sanitation measures at the market are underway. Doctors at Wuhan's Jinyintan Hospital request that the Wuhan Institute of Virology under the Chinese Academy of Sciences conduct whole-genome sequencing on samples from six patients. World Health Organization (WHO) headquarters in Geneva learns of "a cluster of pneumonia cases in China" from the ProMED platform. (See " United States (Brookline, MA) ".) WHO headquarters requests that the WHO China Country Office follow up with Chinese authorities. Taiwan's Centers for Disease Control sends an email to WHO. It reads, "News resources today indicate that at least seven atypical pneumonia cases were reported in Wuhan, CHINA. Their health authorities replied to the media that the cases were believed not SARS; however the samples are still under examination, and cases have been isolated for treatment. I would greatly appreciate if you have relevant information to share with us." Taiwan's Central Epidemic Command Center later notes, "To be prudent, in the email we took pains to refer to atypical pneumonia, and specifically noted that patients had been isolated for treatment. Public health professionals could discern from this wording that there was a real possibility of human-to-human transmission of the disease." Between 5 a.m. and 6 a.m. CST : Wuhan's Jianghan District government suspends operation of the Huanan Seafood Wholesale Market linked to cases of atypical pneumonia. (In addition to selling seafood, the market also sold live wild animals, including hedgehogs, badgers, snakes, and turtledoves. ) Vendors tell the news organization Xin Jing Bao that workers wearing masks have been spraying disinfectant in the market late at night since at least December 30, 2019. Morning CST : A team from China's National Institute for Viral Disease Control and Prevention, part of Beijing-based China CDC, visits the Huanan Seafood Wholesale Market and collects 515 environmental samples, which it sends back to the institute for analysis. CDC experts will return on January 12, 2020, to take 70 more samples from stalls where vendors sold wild animals. Other scientists will later fault the team for not undertaking direct animal sampling in the market before it closed, as without such samples, it may be difficult to determine whether animals at the market were reservoirs for the virus. 5:38 p.m. CST : The Wuhan Municipal Public Security Bureau announces on its official Weibo social media account that it has investigated eight people for "spreading rumors." The bureau's announcement states that while medical institutions in the city have admitted multiple pneumonia cases, some netizens posted and shared "inaccurate information" online, creating a "negative social influence." The eight "law breakers" have been "dealt with," the bureau says. It warns others against "manufacturing rumors, believing rumors, or spreading rumors." Chinese Central Television (CCTV), the Xinhua News Agency, and national other news outlets report on the Wuhan Municipal Public Security Bureau's announcement, also warning against spreading rumors. The Hubei Provincial Health Commission reportedly orders genomics companies to stop testing samples from Wuhan and to destroy existing samples. Following the protocols of Article 9 of the International Health Regulations (IHR) (2005), an international agreement on responses to infectious disease outbreaks, WHO's China Country Office formally requests that the government of China provide "verification" of the outbreak. At just after 8 a.m. CST, a senior official of Wuhan Central Hospital subjects Dr. Ai Fen to what she later describes as "an unprecedented and very severe rebuke." The official tells her not to speak to anyone, including her husband, about the pneumonia cases. She will comply, but will later express regret about lives lost because she didn't "keep screaming." Using samples from patients at Wuhan's Jinyintan Hospital, the Wuhan Institute of Virology identifies the novel coronavirus and sequences its genome. China CDC and the Chinese Academy of Medical Sciences (CAMS) receive biological samples from four patients in Hubei Province and begin work to identify the pathogen responsible for their illnesses. About 1:30 p.m. CST : Wuhan Central Hospital's Dr. Li Wenliang, accompanied by a colleague, arrives at the Wuchang Sub-station of the Wuhan Public Security Bureau to discuss his December 30 posts to the WeChat group. Li is required to sign a letter of reprimand, which he will post online on January 31. The letter states that Li's "false statement" "severely disturbed social order" and violated the People's Republic of China's Law on Penalties for Administration of Public Security . (Article 25 of the law prohibits "intentionally disturbing the public order by spreading rumors or making false reports of dangerous situations, epidemic situations, or police actions." ) 5:08 pm CST : The Wuhan Municipal Health Commission reports it has identified 44 patients with symptoms consistent with pneumonia of unknown origin, some of whom worked at the Huanan Seafood Wholesale Market and 11 of whom are severely ill. Professor Yong-zhen Zhang of the Shanghai Public Health Clinical Center and School of Public Health at Fudan University in Shanghai receives biological samples for analysis from Wuhan Central Hospital. The samples are from a 41-year-old pneumonia patient who worked at the Huanan Seafood Wholesale Market in Wuhan and was admitted to Wuhan Central Hospital on December 26, 2019. China CDC completes genomic sequencing of the novel coronavirus, according to a March 26 paper by China CDC experts and others in the The New England Journal of Medicine . (China's official timeline gives January 7 as the date China CDC completed sequencing of the virus.) China's National Health Commission issues a directive on management of biological samples in major infectious disease outbreaks. The directive reportedly "ordered institutions not to publish any information related to the unknown disease, and ordered labs to transfer any samples they had to designated testing institutions, or to destroy them." U.S. Centers for Disease Control and Prevention (U.S. CDC) Director Robert Redfield emails and then speaks with his Chinese counterpart, Gao Fu (George F. Gao), Director-General of China CDC, who tells him about the atypical pneumonia outbreak in Wuhan. (China later says this is the first of 30 briefings it will provide to the U.S. government through February 3. ) Redfield then calls HHS Secretary Alex M. Azar II at home to brief him on the call. Secretary Azar reportedly tells his chief of staff to notify the White House's National Security Council. In its first public statement on the outbreak, WHO tweets, "China has reported to WHO a cluster of pneumonia casesâwith no deathsâin Wuhan, Hubei Province. Investigations are underway to identify the cause of this illness." The tweet appears to reflect that China has formally verified the outbreak, as the WHO China Country Office requested it do on January 1. The U.S. CDC offers to send technical experts to China. U.S. CDC Director Robert Redfield emails China CDC Director-General Gao Fu, saying, "I would like to offer [U.S.] CDC technical experts in laboratory and epidemiology of respiratory infectious diseases to assist you and China CDC in identification of this unknown and possibly novel pathogen." Neither the United States nor China has disclosed how Gao responds, if at all, but no U.S. CDC team goes to China at this time. The Wuhan Municipal Health Commission announces that it has identified 59 patients with symptoms consistent with pneumonia of unknown origin. It states that a preliminary investigation has uncovered no "clear evidence of human-to-human transmission" or infections among medical workers. The team led by Prof. Yong-zhen Zhang of Fudan University in Shanghai identifies a novel coronavirus and sequences its genome. The team reports its work to Chinese authorities and submits the sequence to GenBank, a genetic sequence database operated by the U.S. National Institutes of Health that serves as "an annotated collection of all publicly available DNA sequences." (China's official timelines omit mention of the team's work, perhaps because it was not coordinated by China's National Health Commission. China's official timelines state that successful sequencing of the genome happened two days later, with China CDC's reported sequencing of the virus on January 7. ) WHO issues its first formal public statement on the outbreak, a "disease outbreak news" item. It states, "On December 31, 2019, the WHO China Country Office was informed of cases of pneumonia of unknown etiology (unknown cause) detected in Wuhan City, Hubei Province of China." The statement adds, "Based on the preliminary information from the Chinese investigation team, no evidence of significant human-to-human transmission and no health care worker infections have been reported." WHO says it "advises against the application of any travel or trade restrictions on China based on the current information available on this event." The annual full session of the Wuhan Municipal People's Congress opens. The congress will last five days and occupy 515 of the city's most important citizens, including the city's entire top leadership. While the congress is in session, the Wuhan Municipal Health Commission will issue no updates on the status of the epidemic. U.S. CDC issues a "Watch Level 1 Alert (be aware and practice usual precautions)" for Wuhan, due to "a pneumonia outbreak of unknown cause." It advises travelers to Wuhan to "Avoid animals (alive or dead), animal markets, and products that come from animals (such as uncooked meat)," "Avoid contact with sick people," and "Wash hands often with soap and water." It also advises anyone who has traveled to Wuhan and feels sick to isolate at home except for seeking medical care. HHS Secretary Azar and CDC Director Robert Redfield renew Redfield's offer to send U.S. CDC experts to China, this time in the form of an official letter. Azar later recalls, "We made the offer to send the [U.S.] CDC experts in laboratory and epidemiology of respiratory infectious diseases to assist their Chinese colleagues to get to the bottom of key scientific questions like, how transmissible is this disease? What is the severity? What is the incubation period and can there be asymptomatic transmission?" A 69-year-old patient undergoes neurosurgery at Wuhan Union Hospital. Four days later, he will develop symptoms that will later be identified as those of the novel coronavirus. Following his admission, he will infect 14 medical workers, making him the virus' first identified "super-spreader." Chinese authorities will not disclose infections among medical personnel until January 20. China's leader, Xi Jinping, convenes an all-day meeting of the country's seven-man Politburo Standing Committee, the country's highest decisionmaking body. Media reports of the meeting at the time do not mention the epidemic. In a February 3 speech made public on February 15, however, Xi states that at the January 7 meeting, he "raised a demand for prevention and control of the novel coronavirus pneumonia." 9 p . m . CST : A China CDC team reportedly sequences the genome of the novel coronavirus. Chinese state media will announce this on January 9. The team led by Prof. Yong-zhen Zhang of Fudan University in Shanghai submits an article to the peer-reviewed journal Nature detailing the team's sequencing of the novel coronavirus. In an article with a Hong Kong byline, "New Virus Discovered by Chinese Scientists Investigating Pneumonia Outbreak," The Wall Street Journal is the first major publication to report that Chinese scientists have genetically sequenced a novel coronavirus. The Wall Street Journal says "Chinese scientists" sequenced the virus, but it does not identify them or their institutions. U.S. and Chinese CDC Directors speak by phone about "technological exchanges and cooperation," according to China's official timeline. 9:45 a.m. CST : The Xinhua news agency publishes an interview in which a prominent medical expert states that the pneumonia cases in Wuhan appear to be caused by a novel coronavirus. 10:32 a.m. CST: CCTV reports that on January 7, China CDC successfully sequenced the genome of the novel coronavirus responsible for the Wuhan outbreak. WHO issues a statement about the preliminary determination of a novel coronavirus, observing, "Preliminary identification of a novel virus in a short period of time is a notable achievement." It adds, "WHO does not recommend any specific measures for travelers. WHO advises against the application of any travel or trade restrictions on China based on the information currently available." The annual full session of the Wuhan Municipal People's Congress concludes after five days, during which the Wuhan Municipal Health Commission issued no updates on the epidemic. The Wuhan Institute of Virology is among the institutions that have now developed testing kits. All suspected novel coronavirus patients in Wuhan are tested. Chinese National Health Commission Party Secretary and Director Ma Xiaowei and China CDC Director-General Gao Fu speak separately by telephone with WHO Director General Tedros about the epidemic. According to China's official timeline, the Chinese government shares "specific primers and probes for detecting the novel coronavirus" with WHO. WHO issues "Advice for International Travel and Trade in Relation to the Outbreak of Pneumonia Caused by a New Coronavirus in China." It recommends against entry screening for travelers, stating, "It is generally considered that entry screening offers little benefit, while requiring considerable resources." Reflecting information from China, it states, "From the currently available information, preliminary investigation suggests that there is no significant human-to-human transmission, and no infections among health care workers have occurred." In its first statement since January 5, the Wuhan Municipal Health Commission states that it has identified no new infections since January 3 and that cases preliminarily attributed to novel coronavirus pneumonia stand at 41â18 fewer than the 59 cases of pneumonia of unknown cause the commission reported on January 5. The commission announces the first death of a coronavirus patient, a 61-year-old man who was a long-time customer of the Huanan Seafood Wholesale Market. The commission states again that it has not found evidence of person-to-person transmission or infections among health care workers. 9 :08 a.m. CST : The team led by Prof. Yong-Zhen Zhang of Fudan University in Shanghai becomes the first to share the genomic sequence of the novel coronavirus with the world. Australian virologist Edward C. Holmes tweets that he has posted an "initial genome sequence of the coronavirus associated with the Wuhan outbreak" on Virological.org, a hub for pre-publication data and analyses. On Virological.org, Holmes writes that he is acting on behalf of the consortium of scientists led by Prof. Zhang, and that the team has also deposited the sequence with GenBank. After the Shanghai team's announcement, China CDC's National Institute for Viral Disease Control and Prevention shares three sequences on Global Initiative on Sharing All Influenza Data (GISAID), an international platform for sharing influenza data. Two other Chinese teams share sequences to GISAID, too. WHO tweets, "BREAKING: WHO has received the genetic sequences for the novel #coronavirus (2019-nCoV) from the Chinese authorities. We expect them to be made publicly available as soon as possible." China later says the Chinese institutions that jointly share the genomic sequence with WHO are China CDC, the Chinese Academy of Medical Sciences, and the Wuhan Institute of Virology under the Chinese Academy of Sciences, as designated agencies of the National Health Commission. The annual full session of the People's Congress of Hubei Province opens in Wuhan. It will last five-and-a-half days and involve 683 delegates. Representatives from the U.S. and United Kingdom consulates in Wuhan attend the opening ceremony. While the congress is in session, the Wuhan Municipal Health Commission will issue daily updates, but will report no new infections. Dr. Li Wenliang is hospitalized with symptoms of the novel coronavirus. In a January 31 Weibo micro-blog post, he recalls thinking at this time, "How can the bulletins still be saying there is no human-to-human transmission, and no medical worker infections?" Chinese authorities do not disclose medical worker infections until January 20. A team from China's National Institute for Viral Disease Control and Prevention, part of China CDC, return to the shuttered Huanan Seafood Wholesale Market to collect 70 additional samples from stalls where vendors sold wild animals. China CDC previously collected an initial 515 environmental samples from the market on January 1, 2020. The Shanghai Health Commission orders Dr. Yong-zhen Zhang's laboratory at the Shanghai Public Health Clinical Centre and School of Public Health at Fudan University to close for unspecified "rectification.'" No reason is given. According to Hong Kong's South Morning Post , it is "not clear whether the closure was related to the publishing of the sequencing data before the authorities." WHO issues a statement noting, "China shared the genetic sequence of the novel coronavirus on 12 January, which will be of great importance for other countries to use in developing specific diagnostic tests." WHO also states, "The evidence is highly suggestive that the outbreak is associated with exposures in one seafood market in Wuhan. The market was closed on 1 January 2020. At this stage, there is no infection among healthcare workers, and no clear evidence of human to human transmission." Two experts from Taiwan's Communicable Disease Control Medical Network and its Centers for Disease Control arrive in Wuhan for a two-day visit to investigate the outbreak. With colleagues from the Chinese Special Administrative Regions of Hong Kong and Macao, they visit Wuhan's Jinyintan Hospital, where an official from China's National Health Commission tells them, "limited human-to-human transmission cannot be excluded." One of the Taiwan experts recalls thinking, "that means human-to-human transmission absolutely." The Communist Party's top decisionmaking body, the Politburo Standing Committee, meets in Beijing to discuss reports to be delivered at upcoming annual full meetings of the national legislature, the National People's Congress, and a political advisory body. (Both meetings will subsequently be postponed due to the epidemic.) Chinese media reports on the meeting do not mention the novel coronavirus. Thai authorities confirm the first case of the coronavirus outside of China. The individual confirmed to have the virus is a Chinese national who traveled to Thailand from Wuhan. WHO headquarters tweets, "Preliminary investigations conducted by the Chinese authorities have found no clear evidence of human-to-human transmission of the novel #coronavirus (2019-nCov) identified in #Wuhan, #China." Dr. Maria Van Kerkhove, acting head of WHO's emerging diseases unit, tells a press conference in Geneva the same day, "it is certainly possible that there is limited human-to-human transmission." The Wuhan Municipal Health Commission reports no new infections or deaths, stating that the cumulative number of cases in the city has remained steady at 41. In a question-and-answer statement dated January 14 but posted to its website on January 15, the Wuhan Municipal Health Commission confirms that the case reported by Thai authorities on January 13 is a resident of Wuhan. The commission also answers the question, "Up to now, has there been person-to-person transmission?" The commission answers, "Existing investigative results indicate no clear evidence of person-to-person transmission. We cannot rule out the possibility of limited person-to-person transmission, but the risk of sustained person-to-person transmission is low." The annual full session of the People's Congress of Hubei Province, which opened on January 12, concludes. After the session closes, the Wuhan Municipal Health Commission announces new infections for the first time since January 3. It states that four new infections bring the number of confirmed cases in the city to 45, with two deaths. Chinese leader Xi Jinping arrives in Burma (also known as Myanmar) at the start of a state visit to celebrate the 70 th anniversary of bilateral diplomatic relations and the "China-Myanmar Year of Culture and Tourism." It is his first overseas trip of the year. Chinese media coverage of his trip does not mention the novel coronavirus. U.S. CDC and the Department of Homeland Security's U.S. Customs and Border Protection begin health screenings for travelers arriving from Wuhan at three U.S. airports. The airports, identified as receiving the greatest number of travelers from Wuhan, are San Francisco (SFO), New York (JFK), and Los Angeles (LAX). To celebrate the Lunar New Year, more than 40,000 households in Wuhan's Bubuting neighborhood hold their 20 th annual potluck banquet. Observers later blame the banquet for contributing to the spread of the virus in Wuhan. In a January 22 interview with CCTV, Wuhan Mayor Zhou Xianwang says the decision to go forward with the banquet was "based on the judgment that in this epidemic, transmission between people was limited." Evening CST : A six-person National Health Commission high-level expert group led by Dr. Zhong Nanshan, a hero from China's struggle against SARS in 2002-2003, arrives in Wuhan. Chinese leader Xi Jinping returns to Beijing after a two-day state visit to Burma. In a telephone call, HHS Secretary Azar briefs President Donald J. Trump about the epidemic for the first time. China's National Health Commission confirms the first case of the new coronavirus outside of Hubei Province, in a 66-year-old resident of Shenzhen, Guangdong Province, next to Hong Kong. The patient had traveled to Wuhan on December 29, 2019, developed symptoms on January 3, and returned to Shenzhen on January 4. The Wuhan Municipal Health Commission announces that the city's cumulative total of cases is 62, with two deaths. The Chinese National Health Commission high-level expert team receives a briefing from the Wuhan Municipal Health Commission and visits the Jinyintan Hospital, where novel coronavirus patients are being treated, and Wuhan CDC. At 5 p.m. CST, the expert team boards a plane for Beijing. The Wuhan Municipal Health Commission announces its cumulative case count is 198, an increase of 136 cases from the day before, with three deaths. The city of Wuhan establishes a "Novel Coronavirus Infection Pneumonia Epidemic Prevention and Control Command Center" headed by Wuhan Mayor Zhou Xianwang. 8 a.m. to 12 p.m. CST: The National Health Commission high-level expert group led by Dr. Zhong Nanshan briefs China's cabinet, the State Council, on findings from the group's visit to Wuhan the day before. 5:00 p.m. -7:00 p.m. CST : In a group interview organized by the National Health Commission, the head of the Chinese National Health Commission's High-Level Expert Group, Dr. Zhong Nanshan, publicly confirms for the first time that the novel coronavirus is being transmitted from person to person and that medical personnel have been infected. 7:27 p.m. CST : Xinhua News Agency reports that Chinese leader Xi Jinping has issued an "important instruction" to prioritize prevention and control work. He tells Communist Party and government bodies at all levels to put people's lives and health "in first place." He also orders "timely issuance of epidemic information and deepening of international cooperation." China's National Health Commission classifies the novel coronavirus-caused pneumonia as a Category B statutory notifiable infectious disease under the PRC Law on the Prevention and Treatment of Infectious Diseases . This empowers hospitals to put those with the disease under mandatory isolation or quarantine and allows the government to blockade epidemic areas. The commission also declares the new disease an infectious disease subject to quarantines for the purposes of the PRC Frontier Health and Quarantine Law , allowing authorities to impose quarantines and other measures on travelers entering and exiting China. Experts from the WHO China Country Office and WHO's Western Pacific Regional Office arrive in Wuhan for a brief field visit. They visit Wuhan's Tianhe Airport, Zhongnan Hospital, and Hubei Provincial CDC. They will leave the next day. The Wuhan Municipal Health Commission reports that 15 medical personnel in the city have been infected with the novel coronavirus. 4:00 p.m. CST: At a Guangdong Provincial Government press conference, Dr. Zhong Nanshan, head of the National Health Commission's high-level expert group, discloses that in Wuhan, a single patient infected 14 medical personnel. People's Daily , the authoritative newspaper of the Communist Party Central Committee, breaks its silence on the novel coronavirus epidemic. Its January 21 issue carries six articles on the epidemic, including two on the front page. WHO issues its first situation report on the novel coronavirus. It reports 278 confirmed cases in China and four outside the country. U.S. CDC confirms the first novel coronavirus case in the United States, in a patient who returned from Wuhan on January 15, 2020. U.S. CDC issues a "Watch Level 2 Alert (Practice Enhanced Precautions)" for the pneumonia caused by the novel coronavirus. In addition to advice issued on January 6, U.S. CDC now also advises that older travelers and those with underlying health issues "should discuss travel to Wuhan with their healthcare provider." 2 a.m. CST : Wuhan Municipality's Novel Coronavirus Infection Pneumonia Epidemic Prevention and Control Command Center issues its first order. It states, "From 10 a.m. on January 23, 2020, the entire city's public transportation, subway, ferries, and long-distance travel will be suspended. Without special reasons, city residents must not leave Wuhan. Channels for departing Wuhan from the airport and railway station are temporarily closed." 3 :55 p.m. CST: In an "urgent notice," China's Ministry of Transport orders transportation authorities across China to suspend passenger travel into Wuhan by road and waterway, and to bar transportation operators from taking passengers out of Wuhan. The epidemic command centers of other cities in Hubei Province start ordering lockdowns. 9:09 p.m. CST: Hubei Province's epidemic command center suspends all intra-provincial flights, trains, buses, and ferry travel in and out of the city of Wuhan. The provinces of Zhejiang, Guangdong, and Hunan are the first to raise their public health emergency response levels to Level I ("extremely significant"), the highest of four levels in China's public health emergency management system. The Level I alert makes provincial governments responsible for coordinating emergency measures related to the epidemic undertaken by government, health authorities, medical institutions, centers for disease control and prevention, and border and quarantine authorities. A WHO Emergency Committee convened under the International Health Regulations (2005) is unable to reach consensus on whether the outbreak constitutes a Public Health Emergency of International Concern. The committee requests to reconvene in 10 days' time. The 15-member body includes a U.S. citizen, Dr. Martin Cetron of U.S. CDC, and a citizen of China, Wannian Liang of China's National Health Commission. The State Department orders the mandatory departure of nonemergency U.S. personnel and their family members from the U.S. consulate in Wuhan. National Security Adviser Robert O'Brien briefs President Trump for the first time on "the potential pandemic threat" of the novel coronavirus. Hubei Province's newly-established epidemic command center raises the province's public health emergency response level to Level I. Additional cities in the province impose travel and transport restrictions, putting tens of millions of residents under partial lockdown. An article published in T he Lancet medical journal raises questions about whether Wuhan's Huanan Seafood Wholesale Market is the source of the virus. The co-authors, including experts from Wuhan's leading infectious disease hospital, report that among the first 41 patients identified in Wuhan, the first patient to show symptoms, on December 1, 2019, had no exposure to the market. Two of the next three patients to show symptoms, all on December 10, also had no exposure to the market. WHO updates its advice for international travelers. Whereas on January 10 it advised against entry screening for travelers, it now notes that in the current outbreak "the majority of exported cases were detected through entry screening." It thus "advises that measures to limit the risk of exportation or importation of the disease should be implemented, without unnecessary restrictions of international traffic." President Trump tweets, "China has been working very hard to contain the Coronavirus. The United States greatly appreciates their efforts and transparency. It will all work out well. In particular, on behalf of the American People, I want to thank President Xi!" The State Department raises its travel alert for Hubei Province to Level 4 ("Do not travel"), its highest alert level, due to the coronavirus outbreak. Lunar New Year's Day, also known as Spring Festival. China's Politburo Standing Committee meets for the third time since January 7. This is the first meeting at which the novel coronavirus is contemporaneously acknowledged to be on the agenda. State media reports the body discusses prevention and control of the outbreak and establishes a high-level working group, known as a central leading group, to oversee control efforts. By 9 p.m. CST, 30 of mainland China's 31 provincial-level jurisdictions have raised their public health alerts to Level I. The only such jurisdiction not to do so is Tibet, which has not so far identified a suspected or confirmed case of novel coronavirus infection. China's National Institute for Viral Disease Control and Prevention, part of China CDC, announces it has confirmed the presence of the novel coronavirus in environmental samples collected from Wuhan's Huanan Seafood Wholesale Market earlier in the month. According to Xinhua, 33 of 585 samples from the market test positive. Of these, all but two were collected from an area of the market where wildlife vendors were concentrated. Xinhua says the results indicate "the virus stems from wild animals on sale at the market." The Communist Party of China announces the establishment of the new top-level Party body focused on combating the epidemic, the Central Leading Small Group for Work to Counter the Novel Coronavirus Infection Pneumonia Epidemic. The Party names Premier Li Keqiang, the Communist Party's second-most senior official, to head the body. At a press conference in Beijing, a senior official says his ministry is working to divert personal protective equipment (PPE) that Chinese factories make for exportâabout 50,000 sets a dayâto domestic use. Vice Minister Wang Jiangping of the Ministry of Industry and Information Technology presents the challenge as one of tweaking China's standards rules to allow PPE made to European and U.S. standards to be used in China. Wang says China has also begun procuring PPE from abroad, with 220,000 sets of PPE purchased on the international market currently on their way to China. In a nationally televised interview, Wuhan Mayor Zhou Xianwang acknowledges having failed to disclose information "in a timely manner" and says China's Law on Prevention and Control of Infectious Diseases restricted Wuhan from sharing information without permission from higher-ups. Zhou also acknowledges that an estimated 5 million people left Wuhan before travel restrictions went into effect. Premier Li Keqiang, head of the Communist Party's Leading Group on Prevention and Control of the Novel Coronavirus Epidemic, visits Wuhan and thanks front-line workers. In an effort to reduce the movement of people across the country, China's government extends the Lunar New Year Holiday to February 2, 2020. It had originally been scheduled to last from January 24 to 30. The government will later extend the holiday to February 13, 2020, in Hubei Province. HHS Secretary Azar speaks to the Chinese National Health Commission Director Ma Xiaowei, and repeats his offer to send a U.S. CDC team to China to assist with COVID-19 public health response efforts. Neither side discloses how Minister Ma responds, if at all, but no CDC team goes to China at this time. Weigong Zhou, an employee of U.S. CDC, and Clifford Lane, an employee of the U.S. National Institutes of Health (NIH), will, however, participate in a WHO-China Joint Mission to China from February 16 to 24. President Trump tweets, "We are in very close communication with China concerning the virus. Very few cases reported in USA, but strongly on watch. We have offered China and President Xi any help that is necessary. Our experts are extraordinary!" U.S. CDC issues its highest-level travel health notice, Level 3, recommending that travelers avoid all nonessential travel to China. The State Department raises its own travel advisory for all of China to Level 3 of 4, urging U.S. citizens to "reconsider travel" to China, while retaining its Level 4 travel advisory for Hubei Province. China's Supreme People's Court criticizes Wuhan Public Security Bureau officers for their reprimand of the eight Wuhan citizens accused of spreading rumors about the new disease. "It might have been a fortunate thing if the public had believed the 'rumors' then and started to wear masks and carry out sanitization measures, and avoid the wild animal market," the court posts on its WeChat account. President Xi Jinping and WHO Director-General Tedros Adhanom Ghebreyesus meet in Beijing. According to WHO, they agree "that WHO will send international experts to visit China as soon as possible." (They will begin their mission to China nearly three weeks later, on February 16.) WHO also requests that China "share biological material with WHO," indicating that China has not yet shared biological samples with WHO. WHO quotes Tedros as saying, "We appreciate the seriousness with which China is taking this outbreak, especially the commitment from top leadership, and the transparency they have demonstrated, including sharing data and [the] genetic sequence of the virus." WHO raises its global level risk assessment to "high," one rung below its risk assessment for China, which is "very high." A U.S. State Department-organized charter flight leaves Wuhan carrying 195 U.S. government personnel and their family members, private U.S. citizens and their family members, and some third country nationals. The flight will arrive in California the same day. The United States is the first country to evacuate its citizens from Wuhan. The State Department will organize four more evacuation flights from Wuhan before the end of February. Secretary of State Michael R. Pompeo speaks by telephone with Yang Jiechi, a member of the Communist Party of China's 25-person Politburo, the country's second highest decisionmaking body. The call is the most senior-level U.S.-China conversation related to the novel coronavirus to date. According to the State Department, Pompeo "expressed condolences for the Chinese citizens who lost their lives as a result of the coronavirus outbreak." He also thanked Yang for assistance in evacuating Americans from Wuhan. According to China's state news agency, Xinhua, "Pompeo conveyed sympathy for the casualties" in China and "expressed appreciation for China's timely response to U.S. concerns after the outbreak of the epidemic." The State Department authorizes the voluntary departure of nonemergency personnel and family members of U.S. government employees from remaining diplomatic posts in mainland China: the Embassy in Beijing and consulates in the Chinese cities of Chengdu, Guangzhou, Shanghai, and Shenyang. WHO Director-General Tedros reconvenes the Emergency Committee under the International Health Regulations (2005). The committee advises him that the novel coronavirus outbreak constitutes a "Public Health Emergency of International Concern" (PHEIC). Tedros declares the PHEIC. He states, "Let me be clear: this declaration is not a vote of no confidence in China. On the contrary, WHO continues to have confidence in China's capacity to control the outbreak." He also states, "WHO doesn't recommend limiting trade and movement." At a campaign rally in Iowa, President Trump states, "maybe we've never had a better relationship [with China] and we[']re working with them very closely on the Coronavirus. We're working with them very, very closely. We only have five people [infected]. Hopefully everything's going to be great. They have somewhat of a problem, but hopefully it's all going to be great. But, we're working with China just so you know, and other countries very, very closely, so it doesn't get out of hand, but it's something that we have to be very, very careful with, right? We have to be very careful." The President announces the formation of the President's Coronavirus Task Force, headed by HHS Secretary Azar, with coordination provided by the National Security Council. The State Department elevates its travel advisory for all of China to Level 4 ("do not travel") and advises Americans in China to "consider departing using commercial means." Daily confirmed cases peak in areas of China outside Hubei, with 875 new confirmed cases reported outside the province. Dr. Li Wenliang posts to social media platform Weibo from his iPhone, recounting the details of his encounter with the law and his struggle with the virus. The next day, Li will share in his last-ever social media post that he has tested positive for the novel coronavirus. Li will die from COVID-19 on February 7, at age 33. The State Department orders the departure of all under-age-21 family members of U.S. personnel in China. President Trump signs Proclamation 9984, effective February 2, suspending entry into the United States of most foreigners who were physically present in mainland China during the preceding 14-day period. The order does not apply to lawful permanent residents, most immediate relatives of U.S. citizens and lawful permanent residents, and some other groups. HHS Secretary Azar declares a public health emergency for the United States "to aid the nation's healthcare community in responding to 2019 novel coronavirus." He also announces that beginning February 2, all U.S. citizens returning to the United States who have been in Hubei Province in the previous 14 days will be subject to up to 14 days of mandatory quarantine. Azar states, "The United States appreciates China's efforts and coordination with public health officials across the globe and continues to encourage the highest levels of transparency." WHO's daily situation report reports a cumulative tally of 9,748 confirmed cases in mainland China and 78 cases in the rest of the world. First identified in Wuhan, China, in December 2019, coronavirus disease 2019 (COVID-19) is now a global pandemic. The timeline below includes key developments in the responses of China, the World Health Organization (WHO), and the United States through January 31, 2020, the day U.S. Department of Health and Human Services (HHS) Secretary Alex M. Azar II declared the pandemic had become a public health emergency for the United States. Late December: Hospitals in Wuhan, China identify cases of pneumonia of unknown origin. December 30: The Wuhan Municipal Health Commission issues "urgent notices" to city hospitals about cases of atypical pneumonia linked to the city's Huanan Seafood Wholesale Market. The notices leak online. | Wuhan medical workers, including ophthalmologist Li Wenliang, trade messages about the cases in online chat groups. December 31: Chinese media outlets confirm the authenticity of the official "urgent notices" that spread online overnight and publish reports about the outbreak. A machine translation of one such media report is posted to ProMED, a U.S.-based open-access platform for early intelligence about infectious disease outbreaks. WHO headquarters in Geneva sees the ProMED post. Following protocols established in International Health Regulations (IHR) (2005), an international health agreement, WHO headquarters instructs the WHO China Country Office to request verification of the outbreak from China's government. | The Wuhan Municipal Health Commission issues its first public statement on the outbreak, saying it has identified 27 cases. January 1: WHO's China Country Office requests China verify the outbreak. | Wuhan authorities shut down the city's Huanan Seafood Wholesale Market. A Chinese Center for Disease Control and Prevention (China CDC) team collects environmental samples from the closed market for analysis. | Wuhan's Public Security Bureau announces it has investigated eight people for "spreading rumors" about the outbreak. January 3: Dr. Li Wenliang is summoned to a local police station, where he is reprimanded for spreading allegedly false statements about the outbreak online. | China CDC Director-General Gao Fu (George F. Gao) tells U.S. Centers for Disease Control and Prevention (U.S. CDC) Director Robert Redfield about a respiratory illness spreading in Wuhan. January 4: In its first public statement on the outbreak, WHO tweets, "China has reported to WHO a cluster of pneumonia casesâwith no deathsâin Wuhan, Hubei Province." The tweet appears to confirm China's government has verified the outbreak to WHO under IHR (2005). January 5: A team led by Prof. Yong-zhen Zhang of Fudan University in Shanghai sequences the novel coronavirus' genome and deposits it in the U.S. National Institutes of Health's GenBank database of publicly available DNA sequences. January 6: Department of Health and Human Services (HHS) Secretary Alex M. Azar II and U.S. CDC Director Redfield offer to send U.S. CDC experts to China. | U.S. CDC issues a "Watch Level 1 Alert" for Wuhan due to "a pneumonia outbreak of unknown cause" and advises travelers to Wuhan to avoid animals, animal markets, and animal products. January 7: China CDC reportedly sequences the genome of the novel coronavirus. January 11 : Prof. Yong-zhen Zhang's team posts the genetic sequence of the virus on open-access platform Virological.org, becoming the first to share it with the world. | China CDC and two other teams post additional genetic sequences of the virus on Global Initiative on Sharing All Influenza Data (GISAID), another open-access platform. | China shares the virus' genomic sequence with WHO. | WHO issues guidance for international travel, recommending against entry screening for travelers. January 12: Dr. Li Wenliang is hospitalized with symptoms of the novel coronavirus. He will die from the disease on February 7. January 13: Thai authorities announce the first case of the novel coronavirus outside China. | Experts from Taiwan and the Chinese Special Administration Regions of Hong Kong and Macao visit Wuhan. A National Health Commission official tells them "limited human-to-human transmission cannot be excluded." January 14: WHO headquarters tweets, "Preliminary investigations conducted by the Chinese authorities have found no clear evidence of human-to-human transmission." The acting head of WHO's emerging diseases unit tells a press conference in Geneva, "it is certainly possible that there is limited human-to-human transmission." January 17: The Wuhan Municipal Health Commission states cases in the city stand at 45, with two deaths. | U.S. CDC and the U.S. Customs and Border Protection begin health screenings for travelers arriving from Wuhan at three U.S. airports. January 18: In a telephone call, HHS Secretary Azar briefs President Trump about the epidemic for the first time. January 20: The head of a high-level Chinese National Health Commission expert team, Dr. Zhong Nanshan, confirms person-to-person transmission of the novel coronavirus and infections among medical workers. | Wuhan establishes an epidemic prevention and control command center. | China declares the disease caused by the novel coronavirus a statutory notifiable infectious disease under the PRC Law on the Prevention and Treatment of Infectious Diseases and an infectious disease for the purposes of the PRC Health and Quarantine Law , opening the way for mandatory quarantines and lock downs. | Communist Party General Secretary Xi Jinping issues an "important instruction" to prioritize epidemic prevention and control work and orders "timely issuance of epidemic information and deepening of international cooperation." | Experts from WHO's China Country Office and its Western Pacific Regional Office arrive in Wuhan for an overnight visit. January 21: WHO issues its first situation report on the novel coronavirus. | U.S. CDC confirms the first novel coronavirus case in the United States, in a patient who returned from Wuhan on January 15, 2020. January 23: At 2 a.m. CST, Wuhan's new epidemic command center issues its first order, suspending public transportation and barring residents from leaving the city, effective at 10 a.m. | Provinces around China begin raising their public health alerts to Level I ("extremely significant"), making provincial governments responsible for coordinating emergency measures related to the epidemic. | An Emergency Committee convened by WHO under IHR (2005) does not reach consensus on whether the outbreak constitutes a Public Health Emergency of International Concern. | The U.S. State Department orders the mandatory departure of nonemergency U.S. personnel and their families from the U.S. Consulate in Wuhan. | National Security Adviser Robert O'Brien briefs President Donald J. Trump for the first time on "the potential pandemic threat" of the novel coronavirus. January 24: Additional cities in Hubei Province impose travel and transport restrictions, putting much of the province of 59 million under partial lockdowns. | WHO updates its advice for international travelers to advise measures to limit the risk of importing the disease, including entry screening. | President Trump tweets, "China has been working very hard to contain the Coronavirus. The United States greatly appreciates their efforts and transparency." January 25: China's most senior decisionmaking body, the seven-man Communist Party Politburo Standing Committee, meets for the third time since January 7. For the first time, the novel coronavirus is contemporaneously acknowledged to be on the agenda. | All but one of mainland China's 31 provincial-level jurisdictions have by now raised their public health alerts to Level I. January 26: China CDC announces it has identified the novel coronavirus in samples collected from Wuhan's Huanan Seafood Wholesale Market earlier in the month. State media suggest this indicates the virus came from wild animals sold at the market. | At a press conference in Beijing, a Vice Minister of Industry and Information Technology says he is working to make personal protective equipment (PPE) manufactured for export available for domestic use. January 27: Premier Li Keqiang, head of a new Communist Party body on prevention and control of the epidemic, visits Wuhan. He is the first member of the Politburo Standing Committee to visit. | HHS Secretary Azar speaks to China's Minister of Health and repeats his offer to send a U.S. CDC team to China. | President Trump tweets, "We have offered China and President Xi any help that is necessary." January 28: Chinese leader Xi Jinping and WHO Director-General Tedros Adhanom Ghebreyesus meet in Beijing. Xi agrees to accept a visit from a WHO international expert team. (The mission will begin February 16.) WHO requests that China "share biological material with WHO," indicating China has not so far done so. | WHO raises its global level risk assessment to "high," one rung below its risk assessment for China, which is "very high." | China's Supreme People's Court criticizes the Wuhan Public Security Bureau for its reprimand of the eight Wuhan citizens accused of spreading rumors about the new disease. January 29: A U.S. State Department-organized charter flight carrying U.S. government personnel, their families, and private U.S. citizens evacuated from Wuhan arrives in California. | Secretary of State Michael R. Pompeo speaks by telephone with Yang Jiechi, a member of China's second highest decisionmaking body, the Communist Party's 25-person Politburo. The call is the highest-level U.S.-China conversation related to the novel coronavirus to date. Pompeo expresses condolences for Chinese lives lost in the outbreak and thanks Yang for China's assistance in evacuating the Americans from Wuhan. January 30: WHO Director-General Tedros declares the epidemic a Public Health Emergency of International Concern. | President Trump states, "maybe we've never had a better relationship" with China, and says the two countries are working together "very closely" to respond to the epidemic. | The President announces the formation of the President's Coronavirus Task Force, headed by HHS Secretary Azar, with coordination provided by the National Security Council. | The State Department elevates its travel advisory for all of China to Level 4 ("do not travel") and advises Americans in China to "consider departing using commercial means." January 31: President Trump signs Proclamation 9984, suspending entry into the United States of most foreigners who were physically present in mainland China during the preceding 14-day period, effective February 2. | HHS Secretary Azar declares a public health emergency for the United States "to aid the nation's healthcare community in responding to 2019 novel coronavirus." He also announces that beginning February 2, all U.S. citizens returning to the United States who have been in Hubei Province in the previous 14 days will be subject to up to 14 days of mandatory quarantine. | WHO's daily situation report reports a cumulative total of 9,748 confirmed cases in mainland China and 78 cases in the rest of the world.

Summary: In Congress, multiple bills and resolutions have been introduced related to China's handling of a novel coronavirus outbreak in Wuhan, China, that expanded to become the coronavirus disease 2019 (COVID-19) global pandemic. This report provides a timeline of key developments in the early weeks of the pandemic, based on available public reporting. It also considers issues raised by the timeline, including the timeliness of China's information sharing with the World Health Organization (WHO), gaps in early information China shared with the world, and episodes in which Chinese authorities sought to discipline those who publicly shared information about aspects of the epidemic. Prior to January 20, 2020âthe day Chinese authorities acknowledged person-to-person transmission of the novel coronavirusâthe public record provides little indication that China's top leaders saw containment of the epidemic as a high priority. Thereafter, however, Chinese authorities appear to have taken aggressive measures to contain the virus. The Appendix includes a concise version of the timeline. A condensed version is below: Late December: Hospitals in Wuhan, China, identify cases of pneumonia of unknown origin. December 30: The Wuhan Municipal Health Commission issues "urgent notices" to city hospitals about cases of atypical pneumonia linked to the city's Huanan Seafood Wholesale Market. The notices leak online. | Wuhan medical workers, including ophthalmologist Li Wenliang, trade messages about the cases in online chat groups. December 31: A machine translation of a Chinese media report about the outbreak is posted to ProMED, a U.S.-based open-access platform for early intelligence about infectious disease outbreaks. WHO headquarters in Geneva sees the ProMED post and instructs the WHO China Country Office to request verification of the outbreak from China's government. | The Wuhan Municipal Health Commission issues its first public statement on the outbreak, saying it has identified 27 cases. January 1: Wuhan authorities shut down the city's Huanan Seafood Wholesale Market. January 3: Dr. Li Wenliang is reprimanded by local Wuhan police for spreading allegedly false statements about the outbreak online. | Chinese Center for Disease Control and Prevention (China CDC) Director-General Gao Fu tells U.S. Centers for Disease Control and Prevention (U.S. CDC) Director Robert Redfield about a pneumonia outbreak in Wuhan. January 4: In its first public statement on the outbreak, WHO tweets, "China has reported to WHO a cluster of pneumonia casesâwith no deathsâin Wuhan, Hubei Province." January 6: Department of Health and Human Services (HHS) Secretary Alex M. Azar II and U.S. CDC Director Redfield offer to send U.S. CDC experts to China. | U.S. CDC issues a "Watch Level 1 Alert" for Wuhan and advises travelers to Wuhan to avoid animals, animal markets, and animal products. January 11 : A team led by Prof. Yong-zhen Zhang of Fudan University in Shanghai posts the genetic sequence of the virus on an open-access platform, sharing it with the world. | China CDC and two other Chinese teams subsequently also post genetic sequences of the virus on an open-access platform. | China shares the virus' genomic sequence with WHO. January 1 2: Dr. Li Wenliang is hospitalized with symptoms of the novel coronavirus. January 20: China confirms person-to-person transmission of the novel coronavirus and infections among medical workers. January 21: U.S. CDC announces the first novel coronavirus case in the United States, in a patient who returned from Wuhan on January 15, 2020. January 23: Wuhan suspends public transportation and bars residents from leaving the city. January 28: Chinese leader Xi Jinping and WHO Director-General Tedros Adhanom Ghebreyesus meet in Beijing. January 30: WHO Director-General Tedros declares the epidemic a Public Health Emergency of International Concern. | President Trump announces the formation of the President's Coronavirus Task Force. January 31: President Trump suspends entry into the United States of most foreigners who were physically present in mainland China during the preceding 14-day period, effective February 2. | HHS Secretary Azar declares a public health emergency for the United States to aid response to the novel coronavirus.