|Home||Founder||What's New||In The News||Consulting|
Paradigm Shift Intervention Monitoring
Haemagglutination inhibition (HI) tests
using postinfection ferret antisera indicated that A(H1N1)pdm09 viruses
remained antigenically homogeneous and closely related to the vaccine
virus A/California/7/2009. Sequence analysis of the HA genes of
A(H1N1)pdm09 viruses indicated that the viruses fell into three genetic
subgroups which were antigenically indistinguishable. A small number of
viruses showed reductions in reactivity with some ferret antisera in HI
The above comments are from the newly released WHO document on the recommended 2011/2012 vaccine targets, “Recommended composition of influenza virus vaccines for use in the 2011-2012 northern hemisphere influenza season,” which keeps all three targets (pandemic H1N1, seasonal H3N2, influenza B) unchanged from the recommendations for the 2010/2011 season. As indicated above, this recommendation is heavily dependent on antigen characterization tests which use ferret reference sera to characterize new isolates.
However, the track record for this assay is abysmal due to a lack of reproducibility, intra and inter-lab variation, low sensitively, and results which are inconsistent with clinical data. The failures have been glaring for the H1N1 target (both seasonal and pandemic) since the 2007/2008 season, and the above recommendation is clearly at odds with the reports of widespread pandemic H1N1 activity in countries and regions where pandemic H1N1 was widespread last season, as well as published and anecdotal reports on vaccine breakthroughs. Moreover, the latest Pneumonia & Influenza death rate for the latest reporting period in the United States (week 6) is near historic highs and well above the rate recorded last season. These examples of immunological escape this season signal more evolution away from the 2009 isolate, California/7, which is the recommended target for next season.
The shortcomings of the antigen characterization test are detailed here, and discussed in depth here.
The reliance of WHO and the CDC on this fatally flawed test continues to be hazardous to the world’s health and a revised method for the selection of influenza vaccine targets is long overdue.