This flu season may be a bad one. Why? Because the flu vaccine produced and already administered to millions may not contain the correct vaccine. In other words, the vaccine Americans take this year, which is developed based on the virus that affects the southern hemisphere, will possibly be ineffective.
The southern hemisphere was afflicted by influenza A (H3N2) virus. Our vaccine contains the component against that virus. But over the summer, “the influenza A (H3N2) virus acquired seven mutations” and is now a very different organism. We know this because the United Kingdom has seen higher than normal flu rates among young adults and school-age children, caused by the mutated virus. This mutation is said to be more serious in its severity compared to the original strain. The new variant has been named “subclade K.” “Subclade K” has caused a flu epidemic in Japan, and is projected to be the main causative virus in the rest of the northern hemisphere.
So, what do we do? Get vaccinated, if you haven’t been. “Even a mismatched vaccine has protective benefits.” Vaccination stimulates the immune system, and though it targets a different virus, it may help your case of flu to be less severe.
Reference: Splete H. New Flu Strain Poised for Possible Takeover. Medscape 2025 November 14.
