On 11 and 12 January 2020, WHO received further detailed information from the National Health Commission about the outbreak. WHO is reassured of the quality of the ongoing investigations and the response measures implemented in Wuhan, and the commitment to share information regularly. 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, andno clear evidence of human to human transmission. The Chinese authorities continue their work of intensive surveillance and follow up measures, as well as further epidemiological investigations. Among the 41 confirmed cases, there has been one death. This death occurred in a patient with serious underlying medical conditions. 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 kits. The cluster was initially reported on 31 December 2019, when the WHO China Country Office was informed. The Chinese authorities identified a new type of coronavirus (novel coronavirus, nCoV), which was isolated on 7 January 2020. Laboratory testing was conducted on all suspected cases identified through active case finding and retrospective review. Other respiratory pathogens such as influenza, avian influenza, adenovirus, Severe Acute Respiratory Syndrome coronavirus (SARS-CoV), Middle East Respiratory Syndrome coronavirus (MERS-CoV) were ruled out as the cause. According to information conveyed to WHO by Chinese authorities on 11 and 12 January, 41 cases with novel coronavirus infection have been preliminarily diagnosed in Wuhan City. Of the 41 cases reported, seven are severely ill. This is when the one death, mentioned above, was reported, in a patient with other underlying health conditions. Six patients have been discharged from hospital. Symptom onset of the 41 confirmed nCoV cases ranges from 8 December 2019 to 2 January 2020. No additional cases have been detected since 3 January 2020. The clinical signs and symptoms reported are mainlyfever, with a few cases havingdifficulty in breathing, and chest radiographs showinginvasive pneumonic infiltrates in both lungs. National authorities report that patients have been isolated and are receiving treatment in Wuhan medical institutions. According to the preliminary epidemiological investigation, most cases worked at or were handlers and frequent visitors to the Huanan Seafood Wholesale Market. The government reports that there is no clear evidence that the virus passes easily from person to person. Currently, no case with infection of this novel coronavirus has been reported elsewhere other than Wuhan. Public Health Response China's National Health Commission has deployed a group of experts to Wuhan City to support the local response. National authorities have reported the following response measures: A total of 763 close contacts including healthcare workers, have been identified and followed up and no additional cases of infection with the novel coronavirus have been identified; The Wuhan Municipal Health Commission carried out active case finding, and retrospective investigations of the current cluster of patients have been completed The Huanan Seafood Wholesale Market has been temporarily closed to carry out environmental sanitation and disinfection ; Public risk communication activities have been carried out to improve public awareness and adoption of self-protection measures. WHO is closely monitoring the situation and is in regular contact with national authorities in China to provide support required. Technical guidance on novel coronavirus has been developed and will continue to be updated as additional information is available. WHO risk assessment To date, investigations are still under way to assess the full extent of the outbreak. Wuhan city is a major domestic and international transport hub. To date, there have been no reported cases outside of Wuhan City. More comprehensive information and ongoing investigations are also required to better understand the epidemiology, clinical picture, source, modes of transmission, and extent of infection; as well as the countermeasures implemented. WHO advice Based on information provided by national authorities, WHO’s recommendations on public health measures and surveillance for novel coronaviruses apply. WHO does not recommend any specific health measures for travellers. In case of symptoms suggestive of respiratory illness either during or after travel, travellers are encouraged to seek medical attention and share travel history with their healthcare provider. Travel guidance has been updated. WHO advises against the application of any travel or trade restrictions on China based on the information currently available on this event.