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Flu A Dominates MA: See Symptoms & Differences
18 Jan
Summary
- Massachusetts reported 7,514 flu cases during the week of Dec. 28, 2025, to Jan. 3, 2026.
- Influenza Type A accounts for the vast majority of current flu cases in the state.
- Despite a recent drop in hospitalizations, flu activity remains high in Massachusetts.
As of the week ending January 3, 2026, Massachusetts experienced 7,514 lab-confirmed influenza cases, a decrease from the prior week's 8,860. The dominant strain is Influenza Type A, with 6,630 unsubtyped positive results, alongside 439 Type A (H1) and 182 Type A (H3) cases. Influenza B cases numbered 121.
Despite a recent decline in hospitalizations since late December, the state's overall influenza-like illness activity is still rated as "very high." Globally, the 2025-2026 flu season has seen 15 million illnesses, 180,000 hospitalizations, and 7,400 deaths in the U.S. alone. Type A strains, including the mutated "subclade K," represent 94.3% of tested subtypes.
Influenza Type A is generally more severe than Type B and has historically caused pandemics. While both spread similarly and present comparable symptoms, Type A can lead to more serious outcomes. Type C infections typically cause mild illness, and Type D primarily affects animals.
