A type of flu virus that used to sicken people every year hasn't been spotted anywhere on Earth since March 2020. As such, experts have advised that the apparently extinct viruses be removed from next year's flu vaccines.
The now-extinct viruses were a branch of the influenza B family tree known as the Yamagata lineage. Scientists first reported the apparent disappearance of Yamagata viruses in 2021. At that time, experts speculated that precautions taken to stop the spread of COVID-19 — such as masking and social distancing — had not only driven the overall number of flu cases to historic lows but may have completely snuffed out this type of flu virus.
