Title: World Health Organization Advises Removing B/Yamagata Component from Seasonal Flu Vaccines
In a recent development, the World Health Organization (WHO) has recommended the removal of a specific component in seasonal influenza vaccines. This component, which protects against the B/Yamagata lineage of the flu virus, has been deemed unnecessary due to its apparent extinction globally.
The disappearance of influenza viruses belonging to the B/Yamagata lineage coincided with the outbreak of the SARS-CoV-2 virus in March 2020. The following flu season, in 2020-2021, was virtually nonexistent, as the genetic diversity of circulating flu strains significantly collapsed. Experts believe that the B/Yamagata lineage took the hardest hit and is now considered extinct worldwide.
During a recent meeting, WHO advisors unanimously recommended the exclusion of the B/Yamagata lineage component from the 2024 seasonal influenza vaccine. The absence of detection of B/Yamagata lineage viruses has led experts to conclude that there is a very low risk of infection associated with this particular strain.
Including the B/Yamagata component in vaccines could potentially pose a theoretical risk of reintroducing the virus into the population. Prior to its disappearance, influenza vaccines targeted three or four types of seasonal flu, including the B/Yamagata lineage. However, with the current circumstances, WHO advisors believe that its inclusion in vaccines is unnecessary.
It is important to note that the 2023-2024 flu shot composition for the northern hemisphere has already been determined, and it includes the B/Yamagata component. However, this recommendation to exclude the strain from subsequent vaccines suggests that future compositions may exclude this component.
While this decision may raise concerns about potential gaps in the protection provided by flu vaccines, WHO advisors have reassured the public that the risks associated with the reintroduction of the B/Yamagata lineage virus are minimal. Their thorough assessment of the situation indicates that the removal of this component is a precautionary measure to align vaccine compositions with the current global influenza landscape.
As researchers continue to monitor influenza strains closely, WHO and other health organizations across the world will work towards ensuring that seasonal flu vaccines remain effective in combating the evolving flu landscape.
Please note that this news article and the information provided are subject to change or further updates from health authorities and organizations.
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