US flu activity rises early in the West as doctors urge vaccination
Flu activity remains low nationally, but an early rise in the West has prompted calls for vaccination. Experts are examining what a mutation in the predominant H1N1 strain could mean for younger people.
US flu activity is rising unusually early, particularly on the West Coast, prompting doctors to urge vaccination for people aged six months and older, Reuters reported on October 20. The Centers for Disease Control and Prevention says activity remains low nationally, though its surveillance for the week ending October 10 found the West had the highest activity.
According to Reuters, 5% of clinical-laboratory flu tests were positive nationally, while the West Coast positivity rate reached 10.7%, compared with 0.5% there a year earlier. The CDC described early-season activity as higher than usual for this point in the year but still within expected seasonal variation. Its surveillance figures are preliminary and may change as more reports arrive.
What the H1N1 findings show
H1N1 accounted for 242 of the 251 influenza A viruses subtyped by public-health laboratories in the CDC's week-40 report, or 96.4%. Nine were H3N2. Since the week ending May 30, H1N1 has made up 79.3% of reported influenza A viruses, according to the agency.
Reuters reported that this year's H1N1 virus has a mutation called G155E. Jennifer Duchon, a pediatric infectious-disease expert at Mount Sinai Children's Hospital in New York, told Reuters that younger people may face greater risk because many have not encountered this strain. Her hospital had begun seeing some flu cases, she said. It is not clear whether the mutation is driving the early rise or causing more severe illness in younger people.
Jeanne Marrazzo, chief executive of the Infectious Diseases Society of America, said small studies found that antibodies from people exposed to flu in 2025 did not recognize the mutation well, particularly antibodies from teenagers and young adults, Reuters reported. She said the findings warranted attention but were not cause for alarm.
Vaccination as flu activity rises
The CDC says flu vaccines are available for people aged six months and older and that, for most people, vaccination should ideally be offered in September or October. It says vaccination is the most effective tool for preventing serious illness. Reuters reported that two pharmacists had not seen a significant pickup in vaccinations, while manufacturers described demand as consistent with last year.
Read in depth: World
Yemen fighting displaces more than 250,000 as Taiz aid access tightens
UN officials say renewed fighting has driven families from their homes and put food, water and hospital supplies under pressure in Taiz.
Helen Haines attack prompts Australian leaders to warn about political violence
Australian leaders urged restraint after the independent MP was struck outside her Wangaratta office, as police investigated and reported threats against politicians rose.
Sources and context
- Early US flu season, current strain may signal risk for younger people; doctors urge shotsThe Straits Times (Reuters)
- Weekly US Influenza Surveillance Report: Key Updates for Week 40, ending October 10, 2026U.S. Centers for Disease Control and Prevention
AI-assisted article checked against the listed sources. NewsJaws did not conduct interviews or attend the reported events.