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  • Ryan Wittler

The Pandemic May Have Driven a Common Flu Strain to Extinction


Two studies from the Doherty Institute in Melbourne have found that one of the four common influenza virus types might have gone extinct during the pandemic.

Some background:

There are two main types of influenza, A and B, both of which cause seasonal epidemics each year. Each includes two subtypes: A/H3N2 and A/H1N1, which jump from human to animals and cause outbreaks like the swine flu, and B/Victoria and B/Yamagata, neither of which live in animals and cause the common flu.

The studies, one published in Nature Reviews Microbiology and the other still under review, show that the B/Yamagata virus hasn’t been detected anywhere in the world since April 2020.

What’s causing it?

According to lead researcher Dr. Marios Koutsakos, since the B/Yamagata subtype has only circulated among humans, it hasn’t evolved much over the past decade, and since populations have had high levels of vaccination against it, we may have developed high levels of immunity too.

However, it’s the measures taken to control the COVID pandemic both at home and abroad that have been the real drivers. According to Koutsakos, border closures “probably had the biggest impact on global spread,” as limiting peoples’ movement across borders means the virus can’t jump between populations as easily.

Community spread, on the other hand, was blunted due to local pandemic measures like social distancing, masks, closing certain businesses, and hand washing.

The researchers can’t say with certainty that B/Yamagata is gone and it’s possible the virus is living in low levels somewhere around the world, however, Koutsakos told Cosmos that a repeat season of masking, good hygiene, and high levels of vaccinations against influenza may rid us of B/Yamagata once and for all.

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