Yamagata virus removed from flu vaccine, here’s why! : Okezone Health

Yamagata virus removed from influenza vaccine. (Photo: Freepik)

DUAN For more than ten years, the annual flu vaccine has provided protection against four types of influenza virus. However, for the 2024-2025 flu season the vaccine in the United States is undergoing major changes.

At present this vaccine only protects against three influenza subtypes, two from influenza A (H1N1 and H3N2) and one from influenza B (Victoria series). The fourth virus, namely Yamagata, was removed from the vaccine. For the first time since 2012, this vaccine is trivalent, different from the quadrivalent form that has been in use until now.

Why did this change happen?

Launching from live science, Friday (4/10/2024), the decision to remove the Yamagata line from the flu vaccine was based on the conclusion that it is believed that the subtype now extinct. In March 2024, the US Food and Drug Administration (FDA) announced that this year’s vaccine would not cover Yamagata because the virus had rarely caused disease in recent years.

This data was obtained through a global consortium of scientists who regularly isolate influenza viruses from sick patients and analyze their genetic material. FDA made this decision based on recommendations from the Vaccine-Related Biological Products Advisory Committee, which was followed by similar recommendations from the World Health Organization (WHO).

However, the transition of global manufacturers to the new formula may take time. The flu vaccine is designed to protect people against the most common flu subtypes each season.

Scientists predict which strains are likely to circulate by tracking infections in different hemispheres, as flu seasons in the northern hemisphere and south in turn. The flu shot works by preparing the immune system to make antibodies ready to attack the selected strain if the person who received the vaccine is exposed to it.

Scientists began to notice signs that the Yamagata line could disappear in 2021, when they noticed that no case of disease was detected. One proposed explanation is that public health measures during the Covid-19 pandemic, such as wearing masks and maintaining social distancing, have led to a reduction in other respiratory diseases, including influenza. .