Experts have recommended removing the extinct Yamagata flu virus from future vaccines, as it hasn’t been seen since March 2020. The disappearance of the Yamagata viruses was first reported in 2021, and experts speculated that the precautions taken to stop the spread of COVID-19 may have contributed to their extinction. Now, a panel of advisers to the Food and Drug Administration (FDA) has unanimously agreed that the Yamagata viruses should be dropped from the flu shot formulation for the 2024-2025 flu season.
For the past decade, U.S. flu vaccines have protected against four types of flu, including two influenza A strains and two influenza B strains. However, with the removal of the Yamagata lineage, the number of protected strains will fall to three. The advisory committee has been advocating for this change for some time, and in fall 2023, the World Health Organization also recommended the removal of Yamagata viruses on a global scale.
Removing the Yamagata lineage from flu shot formulations could have several benefits. It would increase manufacturers’ production capacity, allowing them to produce more doses. Additionally, it would eliminate any potential risks associated with growing the virus in a lab, which is currently required to make flu vaccines.
Experts have emphasized that there is no need to vaccinate people for a virus that appears to be extinct. Dr. Hana El Sahly, a professor of molecular virology and microbiology at Baylor College of Medicine and chair of the FDA advisory committee, stated that they don’t want to vaccinate individuals for a virus that hasn’t been circulating for several years.
Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a member of the FDA advisory committee, highlighted that this change has been discussed for four years. Despite the consensus among health officials, leaders in the pharmaceutical industry argued that manufacturers would need more time to switch to a trivalent formulation. However, with the FDA advisers pushing ahead, manufacturers are prepared to make trivalent vaccines for the U.S. starting from the upcoming season.
Jerry Weir, director of the FDA’s Division of Viral Products, confirmed that all U.S. flu shot manufacturers have submitted the required regulatory paperwork and should be on track to make trivalent vaccines next season. Other countries will likely follow suit in accordance with their regulatory policies.
As these changes take effect, scientists worldwide will continue to monitor the presence of Yamagata viruses and other flu viruses that infect people. The extinction of the Yamagata lineage serves as a reminder of the impact that public health measures, such as masking and social distancing, can have on the spread of infectious diseases.
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