Exciting news out in a Nature Communications paper (h/t @laurel_bristow)! We already knew that public health measures taken during the pandemic also helped reduce transmission of the flu (and quite dramatically). Compared to previous years, the cases of influenza in the 2020-2021 winter season were incredibly low.
▪️So what does this paper add? Interestingly, one of the 4 common lineages of the influenza virus (B/Yamagata) has not been isolated or sequenced since April 2020. B group influenza viruses typically account for about 25% of flu cases each season (on average). So the fact that this lineage has not been identified this year has positive implications! It is important to note that only a small subset of flu cases are sequenced so the level of certainty that extinction has occurred is not 100%. It is also possible for strains to go into “dormancy”. Either way, not having identified any at all suggests a large reduction, and is great news!
▪️What does this mean for us? If it really has gone extinct, this means we don’t need to include the B/Yamagata antigen in the vaccine formulation! The vaccine could either remain quadrivalent but include a 2nd A group antigen potentially increasing flu vaccine efficacy, or become trivalent which could increase global dose availability.
Here, here, for public health measures!!!