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 cases—with no deaths—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 12: 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
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
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.