According to Gavi, the K variant of the H3N2 flu virus first emerged in the Southern Hemisphere and is now dominant in Japan, with scattered cases in North America and Europe. This strain carries new mutations compared to the J.2 strain, which was selected for the 2025/2026 seasonal vaccine. These mutations have raised concerns about potential "immune escape" from previous infections or vaccinations.
In the UK, this year's flu season began 5 weeks earlier than usual, primarily affecting teenagers and young children. Of all flu cases, 98% were influenza A, with 84% caused by H3N2, and 87% of these were the K variant. This indicates the virus is spreading more easily within communities.
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Illustration of flu vaccine. Photo: Vecteezy |
Illustration of flu vaccine. Photo: Vecteezy
Despite these concerns, initial data from the UK suggests vaccines remain effective. While animal studies showed antibodies from vaccines recognized the virus less efficiently, vaccination still reduced hospitalization by 70-75% for children aged 2-17 and by 30-40% for adults. Consequently, experts recommend that people continue to get flu shots to prevent infection and severe complications from the new virus strain.
Flu is an acute respiratory illness caused by a virus, easily transmitted through respiratory droplets and contaminated surfaces. It typically causes fever, cough, headache, and fatigue. While healthy individuals usually recover within 5-7 days, high-risk groups can develop severe complications such as pneumonia and respiratory failure.
Annual flu vaccination is an effective preventive measure. Various types of vaccines are available, protecting against both influenza A and B strains. These are suitable for different age groups and can reduce the risk of hospitalization by 90% and mortality by 70-80% in high-risk populations.
By Van Ha (Source: Gavi)
