The WHO global influenza surveillance and response system (GISRS)—A future perspective

Hay, Alan J; McCauley, John W

A crucial aspect of GISRS and part of its success is meeting the strict timelines for vaccine virus selection and the manufacture and quality control of vaccine, prior to distribution, a process that takes 6-8 months. 32 Thus, any developments which assist interpretation of the most up-to-date data to anticipate potential future antigenic changes are likely to be beneficial in avoiding a "mismatch" of vaccine to circulating strains, which reduces vaccine effectiveness, as That aside, it is ironic that with all the technical advance in molecular characterisation, antigenic characterisation of H3N2 viruses has become more difficult due to changes in both the specificity and affinity of receptor binding and consequent agglutination of red blood cells from different species, in addition to changes in antigenicity. 42, 47 Conclusive results on antigenic relationships are no longer guaranteed from a simple haemagglutination inhibition (HI) test and antigenic characterisation relies on complementary results from neutralisation assays. 39