Outbreaks and emergencies

Human Infection with Avian Influenza A(H7N9)

12 May 2017

Between 05 and 11 May 2017, 18 additional cases of human infection with avian influenza A(H7N9) virus were published in Disease Outbreak News. The cases reported in the most recent publication in Disease Outbreak News (dated 9 May 2017) were notified to WHO on 30 April 2017. (Source: http://www.who.int/csr/don/09-may-2017-ah7n9-china/en/). As of 11 May, a total of 1439 laboratory-confirmed human infections with avian influenza A(H7N9) virus have been reported to WHO and published in Disease Outbreak News since early 2013.

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.

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: