Latest Recommendations for Seasonal Influenza Vaccination
All persons aged ≥6 months without contraindications should receive annual influenza vaccination, ideally during September or October, with a new 2025 recommendation that children ≤18 years, pregnant women, and all adults receive only thimerosal-free, single-dose formulations 1.
Who Should Be Vaccinated
Annual influenza vaccination is universally recommended for everyone aged ≥6 months and older who lacks contraindications 1, 2. This remains the cornerstone recommendation across all major guidelines.
Priority groups for whom vaccination is particularly important include:
- Persons at high risk of influenza-related complications or hospitalization
- Healthcare workers and caregivers who can transmit influenza to high-risk individuals
- Pregnant women (at any trimester)
- Adults aged ≥65 years
- Children aged 6 months through 8 years
- Individuals at higher risk of avian influenza A(H5N1) exposure 2
Optimal Timing of Vaccination
For most people requiring only one dose, vaccination should occur during September or October 1. This timing balances early protection against potential waning of vaccine-induced immunity, which is particularly concerning in older adults.
Avoid July-August vaccination for most groups:
- Adults, especially those ≥65 years: Avoid July-August vaccination due to documented immune waning before peak influenza season 1
- Pregnant women in first or second trimester: Similarly avoid early vaccination unless later access is uncertain 1
Exception - Children requiring 2 doses:
Children aged 6 months through 8 years who have not received ≥2 trivalent or quadrivalent influenza vaccine doses before July 1,2025, or whose vaccination history is unknown, need 2 doses spaced ≥4 weeks apart. These children should receive their first dose as early as possible, including during July-August if available, to complete the second dose ideally by end of October 1.
Continue vaccination throughout the season:
Vaccination should continue after October and throughout the influenza season as long as influenza viruses are circulating and unexpired vaccine is available 1.
Key Updates for 2025-26 Season
Four important changes distinguish this season's recommendations 1:
Thimerosal-free requirement: Children ≤18 years, pregnant women, and all adults should receive only single-dose formulations free of thimerosal as a preservative (new ACIP recommendation, June 2025)
FluMist self-administration: FDA approved self-administration for recipients aged 18-49 years, or caregiver administration (by caregivers ≥18 years) for children aged 2-17 years (September 2024)
Flublok age expansion: FDA expanded approval to include children and adolescents aged 9-17 years (previously ≥18 years only)
Updated antigenic composition: FDA issued new recommendations for 2025-26 vaccine composition (March 2025)
Vaccine Effectiveness
The 2024-2025 interim data demonstrates meaningful protection 3:
- Children and adolescents (<18 years): 32-60% effectiveness against outpatient influenza; 63-78% against hospitalization
- Adults (≥18 years): 36-54% effectiveness in outpatient settings; 41-55% against hospitalization
These estimates confirm that vaccination substantially reduces medically attended influenza and influenza-associated hospitalization, supporting continued annual vaccination recommendations.
Co-administration with Other Vaccines
Seasonal influenza vaccines can be safely administered concurrently with other vaccines, including COVID-19 vaccines 2. This is particularly important for programmatic efficiency and maximizing coverage of recommended vaccinations.
Common Pitfalls to Avoid
- Don't vaccinate too early: Particularly avoid July-August vaccination in older adults and pregnant women in early pregnancy unless access concerns exist
- Don't forget the second dose: Children requiring 2 doses must receive them ≥4 weeks apart; failure to complete the series leaves them inadequately protected
- Don't delay past October: While September-October is ideal, don't withhold vaccination if patients present later in the season
- Don't use thimerosal-containing multi-dose vials: The new 2025 recommendation specifically requires thimerosal-free formulations for children, pregnant women, and all adults
Additional Cardiovascular Benefit
Emerging evidence demonstrates that influenza vaccination provides protective effects against cardiovascular events 2, adding another dimension to the mortality and morbidity benefits beyond respiratory illness prevention.