How well does the flu vaccine work?

Flu vaccination typically reduces the risk of flu illness by between 40% and 60% during seasons when the flu viruses are well-matched to the flu vaccine. But if you are infected with the virus, the vaccine reduces your chances of getting the flu and passing it on to others, and lessens the severity of symptoms, hospitalizations and death.

It's important to know that each year the flu vaccine is never 100% effective in preventing flu. Vaccine effectiveness varies from year to year, based on the match of the circulating flu types to the strains contained in the vaccine.

• Results from the 2023-2024 U.S. flu season show that in adults vaccine effectiveness against hospitalization ranged from 41% to 44%. Specifically for children and teens less than 18 years, the flu vaccine was 71% effective for preventing symptomatic influenza A illness.
• All vaccines in the 2022-2023 flu season were quadrivalent, meaning they targeted 4 strains of the flu, 2 type A flu viruses (H1N1 and H3N2) and 2 type B flu viruses (Victoria and Yamagata lineage) and were well-matched to the circulating viruses. Each year, flu viruses may mutate, meaning new vaccine components will be needed.
• The current 2024-2025 season vaccines are all trivalent. The influenza B/Yamagata vaccine component is being removed because those viruses have not been detected by global flu surveillance since March 2020.

Commonly used flu vaccines include:

• Afluria
• Flublok
• Fluarix
• FluLaval
• Fluzone, Fluzone High Dose
• Flucelvax
• FluMist (nasal)

Not all vaccines are appropriate for all age groups, so check with your healthcare provider. For example, older people 65 years of age and older should use a vaccine for that age group, when available. FluMist is only approved for people 2 through 49 years of age.

FluMist for self- or caregiver administration (which means you could give it at home), was approved in Sept. 2024, but is not expected to be available until the 2025-2026 influenza season. It will still require a prescription.

Annual influenza vaccination is the best strategy for preventing influenza and its complications. Strains can change from year-to-year, and that's one reason why you need the latest flu vaccine each fall.

The U.S. Centers for Disease Control (CDC) recommends that eligible persons aged 6 months and older receive a yearly flu vaccine. The best time is typically in the early fall (Sept or Oct), but if you miss this window it's never too late to get as flu season often goes through Spring in the U.S.

This is not all the information you need to know about the flu vaccine for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.