Face masks may have helped drive two types of flu viruses to extinction

Face mask requirements are quickly loosening in the US, but many people say they plan to continue wearing masks in certain situations, including during pollen season to reduce allergies and when sick. Pandemic safety measures, including social distancing and wearing face masks, reduced the number of flu infections observed during the most recent flu season — and they may have also squashed the influenza H3N2 clade called 3c3.A.

The pandemic, of course, resulted in a massive change in how people live and interact. Face masks were largely used anytime someone was outside of their home, people remained socially distanced from each other, various travel restrictions and testing requirements were implemented, and many people started regularly washing their hands.

It's perhaps no surprise, then, that influenza and the common cold all but vanished this past winter. Experts have warned that as many people begin abandoning these safety measures, the rate of colds and flu may spike for the next season or two. Going forward, however, developing an influenza vaccine to help protect people during flu season may be easier than before.

According to Stat News, pandemic safety measures may have driven a variety of the influenza A virus H3N2 to extinction, though it's too soon to know for sure. The H3N2 viruses are more diverse than influenza A H1N1 subtypes, making it tricky to distribute a vaccine that'll protect people from any given season's dominant flu strain.

An international database is used to record flu virus infections and monitor their evolution over time. The last time the H3N2 3c3.A clade was uploaded into this database was March 2020, as was the influenza B virus lineage called B/Yamagata. The information was provided by Fred Hutchinson Cancer Research Center computational biologist Trevor Bedford.

These varieties of influenza viruses may still be circulating in some regions and it's too early to say whether they're gone for good. However, it is possible that pandemic safety measures like wearing face masks may have reduced the flu's diversity.