What are the predominant strains of influenza currently circulating?

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Last updated: January 1, 2026View editorial policy

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Current Influenza Strains Circulating

I cannot provide real-time information about which specific influenza strains are currently circulating in your state, as the evidence provided contains historical data from past influenza seasons (2009-2024) rather than current surveillance data.

How to Find Current Strain Information

To determine the predominant influenza strains circulating right now in your area, you should:

  • Check the CDC's FluView Interactive dashboard at www.cdc.gov/flu/weekly/fluviewinteractive.htm, which provides weekly updated surveillance data on circulating influenza strains by region and state 1

  • Contact your state health department for local influenza surveillance reports, as they track predominant strains and activity levels in real-time 1

  • Review WHO's FluNet database for global influenza surveillance data if you need international context 2

Historical Patterns to Inform Expectations

While I cannot tell you what's circulating today, understanding recent patterns may be helpful:

Recent seasonal patterns show that:

  • Influenza A(H1N1)pdm09, A(H3N2), and influenza B viruses (both Victoria and Yamagata lineages) have co-circulated in recent years, with the predominant strain varying by season 1, 2

  • The 2023-2024 season was predominantly influenza A(H1N1)pdm09, though A(H3N2) and B viruses also co-circulated 3

  • H3N2-predominant seasons are typically associated with higher severity, increased hospitalizations, and greater mortality, particularly in young children and older adults 1

  • Influenza activity in the United States typically peaks between December and February, though peak activity can occur as late as April or May 1, 2

Why Real-Time Data Matters

Knowing the current predominant strain is clinically important because:

  • Vaccine effectiveness varies significantly by strain, with recent seasons showing VE ranging from 9% against A(H3N2) to 76% against influenza B/Victoria in children 1

  • H3N2 seasons are associated with higher pediatric mortality and hospitalization rates compared to H1N1 or B-predominant seasons 1

  • Treatment decisions and chemoprophylaxis strategies may be influenced by local strain circulation patterns and resistance profiles 1, 2

For current, actionable information about circulating strains in your state, access the CDC FluView dashboard or contact your state health department directly.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Influenza Virus Types and Characteristics

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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