Navigating the H3N2 Challenge: Strategies for Primary Care this Flu Season

An emerging H3N2 influenza variant is now dominant, raising the risk of a more severe flu season. The variant shows antigenic drift from this season’s vaccine strains, modestly reducing vaccine effectiveness.

H3N2-dominant seasons historically produce higher hospitalization rates and worse outcomes, particularly in people over 65. Recent Southern Hemisphere activity featured prolonged H3N2 transmission and offers an early indicator of Northern Hemisphere trends.

Together, surveillance points to sustained H3N2 circulation with an uneven vaccine match across age groups and shifting strain dynamics this season.

Vaccination remains the primary population-level preventive measure despite reduced match. Early antiviral consideration for symptomatic high‑risk patients, paired with expedited testing to guide timely therapy, is prudent.

Key Takeaways:

• New surveillance indicates modestly lower vaccine effectiveness this season versus prior H3N2 years; the reduction disproportionately affects older adults and people with chronic medical conditions.
• Prioritize timely vaccination outreach and targeted counseling for high‑risk patients; maintain a low threshold for antivirals in symptomatic high‑risk individuals to reduce severe outcomes.
• Expect increased outpatient demand—implement telemedicine triage, dedicated respiratory appointment blocks, and standing protocols for rapid antiviral initiation to sustain throughput and readiness.