CDC is closely monitoring an outbreak of respiratory illness caused by a novel (new) coronavirus (named “2019-nCoV”) that was first detected in Wuhan City, Hubei Province, China and which continues to expand. Chinese health officials have reported tens of thousands of infections with 2019-nCoV in China, with the virus reportedly spreading from person-to-person in parts of that country. Infections with 2019-nCoV, most of them associated with travel from Wuhan, also are being reported in a growing number of international locations, including the United States. Some person-to-person spread of this virus outside China has been detected. The United States reported the first confirmed instance of person-to-person spread with this virus on January 30, 2020.
On January 30, 2020, the International Health Regulations Emergency Committee of the World Health Organization declared the outbreak a “public health emergency of international concernexternal icon” (PHEIC). On January 31, 2020, Health and Human Services Secretary Alex M. Azar II declared a public health emergency (PHE) for the United States to aid the nation’s healthcare community in responding to 2019-nCoV. Also on January 31, the President of the United States signed a presidential “Proclamation on Suspension of Entry as Immigrants and Nonimmigrants of Persons who Pose a Risk of Transmitting 2019 Novel Coronavirusexternal icon“. These measures were announced at a press briefing by members of the President’s Coronavirus Task Forceexternal icon.
Coronaviruses are a large family of viruses that are common in many different species of animals, including camels, cattle, cats, and bats. Rarely, animal coronaviruses can infect people and then spread between people such as with MERS, SARS, and now with 2019-nCoV.
Source and Spread of the Virus
Chinese health authorities were the first to post the full genome of the 2019-nCoV in GenBankexternal icon, the NIH genetic sequence database, and in the Global Initiative on Sharing All Influenza Data (GISAIDexternal icon) portal, an action which has facilitated detection of this virus. CDC is posting the full genome of the 2019-nCoV viruses detected in U.S. patients to GenBank as sequencing is completed.
2019-nCoV is a betacoronavirus, like MERS and SARs, both of which have their origins in bats. The sequences from U.S. patients are similar to the one that China initially posted, suggesting a likely single, recent emergence of this virus from an animal reservoir.
Early on, many of the patients in the outbreak of respiratory illness caused by 2019-nCoV in Wuhan, China had some link to a large seafood and live animal market, suggesting animal-to-person spread. Later, a growing number of patients reportedly did not have exposure to animal markets, indicating person-to-person spread. Chinese officials report that sustained person-to-person spread in the community is occurring in China. Person-to-person spread has been reported outside China, including in the United States and other countries. Learn what is known about the spread of newly emerged coronaviruses.
Situation in U.S.
Imported cases of 2019-nCoV infection in travelers have been detected in the U.S. Person-to-person spread of 2019-nCoV also has been seen among close contacts of returned travelers from Wuhan, but at this time, this virus is NOT currently spreading in the community in the United States.
The U.S. government has taken unprecedented stepsexternal icon related to travel in response to the growing public health threat posed by this new coronavirus, including suspending entry in the United States of foreign nationals who have visited China within the past 14 days. Measures to detect this virus among those who are allowed entry into the United States (U.S. citizens, residents and family) who have been in China within 14 days also are being implemented.
Both MERS and SARS have been known to cause severe illness in people. The complete clinical picture with regard to 2019-nCoV is not fully understood. Reported illnesses have ranged from mild to severe, including resulting in death. Learn more about the symptoms associated with 2019-nCoV.
There are ongoing investigations to learn more. This is a rapidly evolving situation and information will be updated as it becomes available.
Outbreaks of novel virus infections among people are always of public health concern. The risk from these outbreaks depends on characteristics of the virus, including how well it spreads between people, the severity of resulting illness, and the medical or other meas