Recent flu strains circulating this season aren't fully covered by the vaccine. As public health experts with years tracking influenza trends, we explain why—and why the shot still offers real protection.
Two Primary Flu Types
Influenza viruses fall into two main groups: A and B. Influenza B has two key lineages (Victoria and Yamagata), but the standard vaccine targets just one. This year, the other lineage—Victoria—is dominating circulation.
Why Wasn't This Variant in the Vaccine? Each year, the World Health Organization (WHO) convenes global experts to forecast Northern Hemisphere strains, often basing predictions on Southern Hemisphere patterns. It's a science-backed estimate, but not foolproof—this season's call didn't match perfectly.
Key Benefits of Getting the Flu Shot You're still shielded against less common strains, and the vaccine provides partial cross-protection even against mismatches. Expect a second wave with variants better aligned to the shot, per historical patterns.
