Public health relevant virological features of influenza A(H7N9) causing human infection in China

As of 4 April 2013, the China Health and Family Planning Commission notified WHO of a total number of eleven (11) confirmed cases of human infection with influenza A(H7N9) virus in China.

This particular strain of A(H7N9) virus has not previously been detected in human or animal populations. This document describes some key virological features of the three A(H7N9) viruses analysed so far. These virological features are based on initial analyses carried out by the WHO Collaborating Centres for Reference and Research on Influenza in Beijing and Tokyo, and the WHO Collaborating Centre for Surveillance, Epidemiology and Control of Influenza, Atlanta, United States of America.