WHO Risk Assessment of human infection with avian influenza A(H7N9) virus

On 8 April 2014 WHO conducted a risk assessment in accordance with the WHO recommendations for rapid risk assessment of acute public health events.

Taking into consideration all information available to date to WHO, it is concluded that the public health risk from avian influenza A(H7N9) virus has not changed since the previous assessments of 24 and 11 March and 28 February 2014.

 

Risk assessment

What is the risk of the occurrence of further cases in the affected areas of China and Other areas?

The epidemiology of this virus among animals, including the main reservoirs of infection among animals and the extent of geographic spread, is not yet established. However, it is likely that most human H7N9 infections so far are associated with infection among as of yet undetermined animals and that further human cases of infection should be expected.

 

What is the risk of human to human transmission?

There is no evidence of sustained human-to-human transmission. However the two possible family clusters suggest that limited human-to-human transmission may occur where there is close contact between cases and other individuals, as occurs in families and, potentially,

healthcare settings. Moreover, the genetic changes seen among these viruses suggesting adaptation to mammals is of concern, and further adaptation may occur.

 

What is the risk of international spread?

At this time, there is no information to indicate international spread of this virus. However, it is possible that an infected person, who may or may not have symptoms, could travel to another country. However, if the virus cannot sustain human-to-human transmission, as appears to be the current situation, then extensive community spread is unlikely.

WHO does not advise special screening at points of entry with regard to this event, nor does it recommend that any travel or trade restrictions be applied.

Read more: http://www.who.int/influenza/human_animal_interface/influenza_h7n9/RiskAssessment_H7N9_13Apr13.pdf?ua=1