Outbreaks and emergencies

Human Infection with Avian Influenza A(H7N9)

24 February 2017

From 17 to 23 February 2017, 305 cases of human infection with avian influenza A(H7N9) virus were published in Disease Outbreak News. The last case of human infection with avian influenza A(H7N9) virus in the Western Pacific Region published through Disease Outbreak News was notified to WHO 22 February 2017. (Source: http://www.who.int/csr/don/22-february-2017-ah7n9-china/en/). A total of 1,223 laboratory-confirmed human infections with avian influenza A(H7N9) virus were reported to WHO between early 2013 and 22 February 2017.

WHO is continuing to assess the epidemiological situation and will conduct further risk assessments with new information. Overall, the public health risk from avian influenza A(H7N9) viruses has not changed.

Further sporadic human cases of avian influenza A(H7N9) virus infection are expected in affected and possibly neighbouring areas. Should human cases from affected areas travel internationally, their infection may be detected in another country during or after arrival. If this were to occur, community level spread is considered unlikely as the virus does not have the ability to transmit easily among humans.

On 18 February 2017, the National Health and Family Planning Commission of China (NHFPC) reported to WHO the results of genetic sequencing on virus isolates from 2 previously reported cases of human infection with A(H7N9) virus from Guangdong province. Insertions at the cleavage site of the HA gene suggestive of being highly pathogenic to poultry was confirmed by the Chinese National Influenza Centre of the Chinese Centre for Disease Control and Prevention (China CDC).

To date, there has been no evidence of sustained human-to-human transmission of avian influenza A(H7N9) virus. Human infections with the A (H7N9) virus are unusual and need to be monitored closely in order to identify changes in the virus and/or its transmission behaviour to humans as it may have a serious public health impact.

For more information on human infection with avian influenza A (H7N9) virus reported to WHO:

For more information on risk assessment for avian influenza A(H7N9) virus: