WHO: Antigenic and genetic characteristics of H5N1 viruses and candidate H5N1 vaccine viruses developed for potential use as human vaccines

February 2009

This summary describes the current status of the development of new candidate H5N1 vaccine viruses and is meant to provide guidance for national authorities and vaccine companies on the selection of candidate viruses for use in vaccine development. The selection of H5N1 vaccine viruses should consider the geographical spread, epidemiology, and antigenic and genetic properties of recently circulating H5N1 viruses.

Clinical trials using both clade 1 and clade 2 viruses should continue as an essential element in pandemic preparedness.

Full text - February 2009 [pdf 51kb]

Previous summaries

September 2008 [pdf 157kb]
February 2008 [pdf 741kb]
March 2007 [pdf 144kb]
August 2006 [pdf 42kb]