In another study when there was a good match to the circulating strain and influenza did not begin to circulate until after the 10-week post-vaccination time point, we found that a low IFNγ:IL-10 ratio at pre- and 4-weeks post-vaccination predicted increased risk for A/H3N2-LCII only in those who were PCR+ and had febrile (more severe) LCII; importantly this group did not seroconvert to influenza infection [21]. This evidence concerns the gene IL10 and influenza.