11 November 2005
WHO Reference Labs developing new experimental H5N1 vaccine prototype strains
The World Health Organization (WHO) posted online an important 3-paragraph milestone October 28th that reported H5N1 viruses from both birds and humans are “genetically distinguishable from the prototype strains selected last year for influenza pandemic strain development”. Thus “the WHO H5 Reference Laboratory Network, which undertakes the tasks of selecting and developing the pandemic vaccine strains, has initiated the development of experimental H5N1 vaccine prototype strains from the recent viruses”. WHO also reported “evidence of antigenic variation among the HA (hemagglutinin) of recent viruses”.
At the same time WHO stated in the title of this article that they “recommend H5N1 prototype strains for influenza pandemic vaccine development remain the same” referring to “ongoing pandemic vaccine development”, but not for “vaccine research purposes” in which the newer H5N1 viruses will be used to develop experimental H5N1 vaccines.
Notably, WHO stated that “H5 hemagglutinins (HA) genes of viruses from birds in China, Indonesia, Japan, Mongolia, Russia, South Korea, and Turkey, and 3 viruses from humans in Indonesia are genetically distinguishable from the prototype strains selected last year for influenza vaccine development. There is also evidence of antigenic variation among the HA of recent viruses. However, their geographical spread and pathogenicity in human populations remain unclear.”
Clicking on the link to “WHO H5 Reference laboratory Network” cited in this document takes the reader to a 23 March 2004 WHO list of “WHO reference laboratories for diagnosis of influenza A/H5 infection”. These 8 labs are located in Hong Kong (2), France, Japan, the United Kingdom, USA (2), and Australia.
This critical WHO October 28th update on genetic changes and antigenic variation in the immunologically-dominant hemagglutinin (HA) molecule of the H5N1 virus is a new milestone marking the continued evolution of this potentially pre-pandemic H5N1 virus from 1997 to 2002-2003 to 2004-2005.
Once again the tenacious and timely monitoring and decision to take action based on the evolution of the H5N1 virus by initiating new research vaccine development by the WHO is to be appreciated worldwide. Such WHO action, however, would not be possible without the “rapid sharing of avian influenza virus isolates/specimens from affected Member States with the WHO H5 Reference Laboratory Network”.
Daniel R. Lucey, MD, MPH
Director, Center for Biological Counterterrorism and Emerging Diseases
ER One Institutes, Washington Hospital Center
Co-Director, Georgetown Medical School Master of Science Program in
“Biohazardous Threat Agents and Emerging Infectious Diseases”
Washington DC Website: www.BePast.org