Rapid risk assessment: Severe respiratory disease associated with a novel influenza A virus, A(H7N9) China

risk assessment

On 31 March 2013, the Chinese authorities announced the identification of a novel influenza A virus, A(H7N9), in three seriously ill people from two provinces presenting with respiratory infections. So far, no epidemiological link has been identified between those three patients. When testing for the influenza virus, the Chinese Center for Disease Control and Prevention identified genes from both A(H7N9) and A(H9N2) viruses, thus indicating a novel reassortant avian influenza A virus. In its initial assessment of the situation, the ECDC rapid risk assessment concludes that the risk of the spread of the virus in Europe can be considered low at this stage.

Executive summary

On 31 March 2013, the Chinese authorities announced the identification of a novel influenza A virus, A(H7N9), in three seriously ill people from two provinces presenting with respiratory infections. So far, no epidemiological link has been identified between those three patients.

When testing for the influenza virus, the Chinese Center for Disease Control and Prevention identified genes from both A(H7N9) and A(H9N2) viruses, thus indicating a novel reassortant avian influenza A virus. In its initial assessment of the situation, the ECDC rapid risk assessment concludes that the risk of the spread of the virus in Europe can be considered low at this stage. However, individual patients coming from China cannot be ruled out. It is thus important to further investigate the source of infection and the mode of transmission to develop ECDC’s assessment further.

This event stresses the importance of considering the possibility of zoonotic influenza due to novel influenza A viruses in persons presenting with severe acute respiratory disease. Especially when patients have recently been in countries where animal influenza A viruses circulate and these viruses have recently caused severe respiratory disease in humans. This includes China.

ECDC is working closely with WHO and the European Commission and will continue to monitor the situation.

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