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Why H3N2 Influenza Hits Harder
H3N2 influenza, a fast-evolving subtype of Influenza A, causes tougher seasonal waves because of its rapid antigenic drift that weakens prior immunity. Emerging in 1968 via an avian-origin shift, it now dominates many winter outbreaks.
Cold, dry air boosts viral stability, and indoor crowding accelerates spread—seen recently in India’s 2025 winter surveillance and UK subclade spikes. The strain hits hardest in children, elderly adults, pregnant women, and people with asthma/COPD/diabetes, with higher risks of pneumonia and hospitalization.
Symptoms include high fever, dry cough, sore throat, body aches, and fatigue, with peak contagiousness on days 3–4. Transmission occurs via droplets, aerosols and surfaces (up to :48 hours survival). Vaccine protection ranges 40–60%, but mismatch years reduce efficacy. Prevention relies on updated vaccination, early antivirals like oseltamivir , masking in crowded spaces, and adequate rest.
Cold, dry air boosts viral stability, and indoor crowding accelerates spread—seen recently in India’s 2025 winter surveillance and UK subclade spikes. The strain hits hardest in children, elderly adults, pregnant women, and people with asthma/COPD/diabetes, with higher risks of pneumonia and hospitalization.
Symptoms include high fever, dry cough, sore throat, body aches, and fatigue, with peak contagiousness on days 3–4. Transmission occurs via droplets, aerosols and surfaces (up to :48 hours survival). Vaccine protection ranges 40–60%, but mismatch years reduce efficacy. Prevention relies on updated vaccination, early antivirals like oseltamivir , masking in crowded spaces, and adequate rest.