Health · Public Health & Disease · 1 hr ago
Early US flu rise raises concern about H1N1 risk for younger people
Flu cases are rising unusually early on the US West Coast, and doctors are urging Americans aged 6 months and older to get a flu shot.
The main strain this year is H1N1 with a new mutation, a virus type that caused the 2009 swine flu pandemic and is included in the current vaccine.
Scientists say people may have less protection against this version, and younger people may be especially at risk because they have had less exposure to H1N1.
The concern is based on small studies, and experts say it is not a reason for alarm.
The 2026-2027 vaccine targets H1N1, H3N2 and one influenza B virus, and two components appear to match circulating strains well.
Flu vaccines have reduced hospitalisations and deaths by 30% to 60% over the past decade, though their effectiveness varies.
Doctors recommend getting vaccinated early as flu season gains momentum.
Doctors are urging Americans aged 6 months and older to get vaccinated after an unusual early rise in flu cases on the West Coast.
The predominant strain this year is H1N1, and its new G155E mutation may pose a greater risk to younger people.
Experts say people previously exposed to H1N1 may have only partial protection against the newer version.
The 2026-2027 vaccines target H1N1, H3N2 and one influenza B virus.
Experts say the mutation is a concern but that small studies are not cause for alarm.
- Who
- Doctors are urging Americans aged 6 months and older to get vaccinated.
- What
- Flu cases have risen unusually early on the West Coast, and experts are assessing the possible risk from a mutated H1N1 strain.
- When
- The early rise was reported on October 20, 2026.
- Where
- The United States, with the unusual early rise reported on the West Coast.
- Why
- The reason for the early rise is unclear. Experts say a new H1N1 mutation may affect protection, especially among younger people.
This story does not have two clearly opposing sides.
Nearly 75 million American adults received a flu shot.
An estimated 32 million Americans had the flu, 390,000 were hospitalised and 24,000 died.
The FDA approved the 2026-2027 flu vaccines.
Reports described an unusual early rise in flu cases on the West Coast and doctors urged vaccination.
- Predominant strain
- H1N1
- New mutation
- G155E
- Vaccine components
- H1N1, H3N2 and one influenza B virus
- Adults vaccinated last season
- 58 million
- Children vaccinated in 2025
- Around half
- Estimated U.S. flu cases in 2025
- 32 million
3 sources
Strain behind 2009 swine flu pandemic that sickened 60 million returns with new mutation that may leave young people more vulnerable
Early US flu season, current strain may signal risk for younger people; doctors urge shots
Early U.S. flu season, current strain may signal risk for younger people; doctors urge shots
What people are saying
What people are a bit worried about is that the H1N1 strain this year hasn't been seen by a lot of younger folk, so it may be more severe in them
it is probably a good idea to get vaccinated early
There's no clear reason to me why this would be the case,
something to be aware of but not cause for alarm