Flu cases on the West Coast are rising months earlier than normal, and health experts are urging people to get vaccinated now. Flu activity usually ramps up in December and peaks in February, but this season has started early 1.
In California, flu test positivity was 9.65% as of Oct. 10, according to state health department data. In the past two flu seasons it hovered slightly above 1% in early October 1.
A mutated H1N1 strain
Several experts credit the early start to a new mutation of H1N1, the influenza A strain behind the 2009 swine flu pandemic 1. The Centers for Disease Control and Prevention (CDC) says that of 300 positive samples reported by public health labs in the week ending Oct. 10, 292 were influenza A. Of the 251 influenza A viruses that were subtyped, 242 were H1N1 2.
Utah has recorded 242 influenza A cases as of Oct. 11, up from 10 at this time last year, according to Germ Watch, a database run by Intermountain Health. Parts of central Oregon have also seen a surge 1.
The CDC says activity nationally is still low but rising. Its highest levels are on the West Coast. Nationwide, 5.0% of lab tests were positive that week, up from 3.9% the week before. All of the data are preliminary 2.
Why older adults should pay attention
Adults 65 and older had the highest flu hospitalization rate in the CDC's latest report. One tracking network put it at 2.3 per 100,000 people, and a second system put it at 3.8 per 100,000. The second system's rate for all ages was 1.2 per 100,000 2.
The 2026-27 flu vaccines, approved by the Food and Drug Administration in August, target H1N1, H3N2 and one influenza B virus. The American Medical Association says vaccines can reduce severe illness and hospitalization, and it recommends flu shots for everyone 6 months and older 1.
Scott Hensley, a University of Pennsylvania microbiologist, said two of the vaccine's three components appear well matched to circulating strains. He said the H1N1 mutation might affect antibodies in younger people 1.
it is probably a good idea to get vaccinated early
The CDC says the vaccine is ideally given in September or October 2. Hensley also told NPR that this may be a year to get the shot early 3.
Quieter federal promotion
The Guardian reports that promotion of flu shots has been reduced under Health Secretary Robert F. Kennedy Jr., who has overhauled long-standing childhood vaccine schedules 1. NPR reported that the CDC has not been promoting flu shots as it usually does 3.
Demetre Daskalakis resigned last year as director of the CDC's National Center for Immunization and Respiratory Diseases. He criticized the agency's silence, as the quote below shows 3.
It is disappointing that CDC is quiet given that flu kills of hundreds of kids a year
A CDC spokesperson told NPR the agency is developing a communications strategy to provide information about flu vaccination. The agency did not make an official available for the story 3.
That matters because the early surge is arriving with federal public health messaging quieter than usual. Readers can ask a doctor or pharmacist about a flu shot now rather than waiting for winter.
The Record
Sources
- The Guardian, “Flu cases rise on west coast earlier than usual as US health experts encourage vaccine” (2026-10-23). theguardian.com/us-news/2026/oct/22/flu-cases-west-coast-cdc
- CDC, “Weekly US Influenza Surveillance Report: Key Updates for Week 40, ending October 10, 2026” (2026-10-16). cdc.gov/fluview/surveillance/2026-week-40.html
- NPR via GPB, “Early flu season means it might be time to think about a flu shot” (2026-10-07). gpb.org/news/2026/10/07/early-flu-season-means-it-might-be-t
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