alt Hacker NewsIn the US, until very recently, there were four variants in the vaccine: two Influenza A and two Influenza B. But one of the B variants seems to have gone extinct during the COVID pandemic, and now the vaccine is just two A and one B.
In the US, until very recently, there were four variants in the vaccine: two Influenza A and two Influenza B. But one of the B variants seems to have gone extinct during the COVID pandemic, and now the vaccine is just two A and one B.