One Less Kind of Flu in the World!

A branch of the influenza B family tree has entirely disappeared from the surface of the Earth, so much so that authorities in the United States have decided to remove the extinct viruses from next season’s flu vaccines.

“We don’t want to vaccinate you for a virus that’s no longer in circulation for three, four years now,” states Dr. Hana El Sahly, a professor of molecular virology and microbiology at Baylor College of Medicine and chair of the Food and Drug Administration (FDA) advisory committee. 

There hasn’t been an outbreak of the Yamagata lineage, a member of the influenza B family tree, since March 2020. Due to precautions – masking and social distancing, among others – taken to prevent the spread of COVID-19, the number of flu cases was brought to an all-time low, completely wiping out this type of flu. The FDA has unanimously agreed to modify the flu shot formulation for the 2024-2025 flu season. For the past ten years, the flu shot protected civilians against four types of flu – two influenza A strains and two influenza B strains – and by dropping the Yamagata lineage, manufacturers will be able to boost their production capacity and eliminate potential risks associated with growing the virus in a lab, an unavoidable step in the making of the vaccine.