STAT September 29, 2023
The World Health Organization has recommended dropping a component of many flu vaccines because the viruses it protects against appear to have been driven into extinction in the Covid-19 pandemic.
A family of viruses known as influenza B/Yamagata has not been seen since March 2020, when flu circulation worldwide declined to very low levels in the face of the onslaught of Covid and the protections people took to avoid contracting it. Flu transmission eventually resumed, but of the tens of thousands of influenza B viruses detected and subtyped in the years since, B/Yamagata viruses have not been seen.
“It’s no longer needed in the vaccine at this point in time and no longer warranted,” said David Wentworth, director of the...