# Flu is rising early in the West, but CDC says activity remains low Surveillance points to an unusual west-to-east start, led by H1N1, while experts caution that an early uptick alone does not predict a severe season. By The Signal Edition | Health / Infectious disease Published: 2026-10-22T18:30:00Z Updated: 2026-10-22T18:30:00Z Canonical: https://www.thesignaledition.com/article/lhbun-early-influenza-surge-west-coast-20261022 Image: https://www.thesignaledition.com/media/72ba07040fe1c3925f141a0d2e7c65d4.jpg (A nursing student administers a flu shot to a staff member at a Texas A&M University vaccination clinic.; credit: Texas A&M University; image resized and cropped to 1280 × 720.) ## Summary - CDC says flu activity is increasing but remains low overall; its latest report identifies the West Coast as the area with the highest activity. - Five percent of clinical-lab specimens tested positive nationally in the week ending Oct. 10, up from 3.9% the prior week; Reuters reported 10.7% positivity on the West Coast last week versus 0.5% a year earlier. - H1N1 accounted for 96.4% of the influenza A viruses subtyped by public health labs in Week 40. The early rise does not by itself show how severe the season will be. ## An early rise, still low overall Influenza is picking up earlier than usual in parts of the United States, with the strongest activity along the West Coast, but the Centers for Disease Control and Prevention says seasonal flu activity remains low nationally. In its latest weekly FluView report, covering the week ending Oct. 10, the agency said several indicators—including positive tests, flu-like outpatient visits, emergency-department visits and flu-associated hospitalizations—had risen since late August or early September. CDC described the early-season activity as higher than typically seen at this time of year, while still within expected seasonal variation. [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) Nationally, 5.0% of specimens submitted by clinical laboratories tested positive in Week 40, compared with 3.9% the week before. That is a share of tested specimens, not a count of all infections. CDC’s report is preliminary and may change as additional data arrive. [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) ## The West is setting the pace CDC identifies HHS regions 9 and 10—the West Coast regions—as having the highest activity. Reuters, citing the latest surveillance, reported that the West Coast’s positive flu-test rate reached 10.7%, compared with 0.5% at the same point last year. The national clinical-lab positivity figure was 5% last week, Reuters reported, a 10-year high for this time of year. The regional and national percentages describe different populations of tested specimens and should not be read as a direct comparison of case counts. [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) [2](https://www.reuters.com/business/healthcare-pharmaceuticals/early-us-flu-season-current-strain-may-signal-risk-younger-people-doctors-urge-2026-10-20/) The geography is notable because flu often begins in the South before spreading north, Reuters reported. But an early start in the West is not, by itself, a signal of a more dangerous season. Live Science quoted Vanderbilt infectious-disease specialist William Schaffner saying flu can begin in different parts of the country; the outlet also noted that an early start does not guarantee a severe season. [2](https://www.reuters.com/business/healthcare-pharmaceuticals/early-us-flu-season-current-strain-may-signal-risk-younger-people-doctors-urge-2026-10-20/) [3](https://www.livescience.com/health/flu/october-is-the-ideal-time-to-get-vaccinated-flu-season-is-kicking-off-early-experts-say) ## H1N1 leads; severity remains an open question H1N1 is the leading strain in the surveillance so far. Of 251 influenza A viruses subtyped by public-health laboratories in Week 40, 242—or 96.4%—were A(H1N1)pdm09. Across viruses reported since late May, CDC says most H1N1 viruses characterized belong to the D.3.1.1 hemagglutinin subclade. [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) Reuters reported that scientists are examining a G155E mutation in this season’s H1N1 viruses and whether prior exposure may offer less protection to some younger people. The significance is not settled: Reuters quoted experts describing the concern as preliminary, while CDC’s weekly report does not assign a forecast of severity based on this mutation. The surveillance snapshot also cannot establish whether the early geographic pattern will persist as the season develops. [2](https://www.reuters.com/business/healthcare-pharmaceuticals/early-us-flu-season-current-strain-may-signal-risk-younger-people-doctors-urge-2026-10-20/) [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) For prevention, CDC says annual seasonal flu vaccination is recommended for people aged 6 months and older and that, for most people, vaccination should ideally be offered in September or October. That is the agency’s public-health guidance as flu indicators rise; it is not a prediction of how intense the season will become. [1](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) ## Reporting sources 1. [Centers for Disease Control and Prevention: Weekly US Influenza Surveillance Report: Key Updates for Week 40, ending October 10, 2026](https://www.cdc.gov/fluview/surveillance/2026-week-40.html) (2026-10-16) 2. [Reuters: Early US flu season, current strain may signal risk for younger people; doctors urge shots](https://www.reuters.com/business/healthcare-pharmaceuticals/early-us-flu-season-current-strain-may-signal-risk-younger-people-doctors-urge-2026-10-20/) (2026-10-20) 3. [Live Science: Flu season is off to an early start — here's what to know](https://www.livescience.com/health/flu/october-is-the-ideal-time-to-get-vaccinated-flu-season-is-kicking-off-early-experts-say) (2026-10-09)