From the Guidelines
Influenza Vaccination Discontinuation
Stop offering the flu shot when the flu season has ended, typically by March or April in the Northern Hemisphere, or when the vaccine supply has been depleted. However, as a precautionary measure, it's recommended to continue offering the flu shot as long as the vaccine is still potent and the risk of influenza transmission remains, even if it's beyond the typical flu season. In general, the flu shot can be administered until the end of June, or as directed by local health authorities 1.
Key Considerations
- The flu season is unpredictable, and influenza activity can occur in early fall (October) or late spring (end of May), making it essential to continue offering the vaccine as long as it is available and the risk of transmission remains 1.
- International travel may result in potential exposure to influenza throughout the year, emphasizing the need for continued vaccination efforts 1.
- The duration of protection after influenza vaccination can wane over time, but the vaccine can still provide protection against influenza illness, especially among children 1.
- Vaccination efforts should continue throughout the season, and providers should offer influenza vaccine at health care visits to those not yet vaccinated, even after influenza activity has begun in the community 1.
Administration Guidelines
- The flu shot can be administered until the end of June, or as directed by local health authorities 1.
- Vaccine supply and expiration dates should be considered when determining the discontinuation of influenza vaccination efforts 1.
From the Research
Influenza Vaccination Discontinuation
There is no specific guidance on when to discontinue influenza vaccination. However, the following points can be considered:
- The effectiveness of the influenza vaccine wanes over the course of a flu season, and delaying vaccination for older adults has been suggested as a potential public health strategy 2.
- The Advisory Committee on Immunization Practices (ACIP) recommends routine annual influenza vaccination for all persons aged ≥6 months who do not have contraindications 3.
- Vaccination soon after the vaccine becomes available can be considered for pregnant women in the third trimester, while children who need 2 doses should receive their first dose as soon as possible after vaccine becomes available to allow the second dose to be received by the end of October 3.
- For nonpregnant adults, vaccination in July and August should be avoided unless there is concern that later vaccination might not be possible 3.
- Some studies suggest that delaying seasonal influenza vaccine selections for the Northern Hemisphere could have potential benefits, particularly when additional data could help improve the antigenic match between vaccine and circulating viruses 4.
- The effects of prior season vaccination on current season vaccine effectiveness have been studied, and the results support the Advisory Committee on Immunization Practices recommendations for annual influenza vaccination 5.
Key Considerations
- The waning effectiveness of the influenza vaccine over the course of a flu season
- The potential benefits of delaying seasonal influenza vaccine selections
- The effects of prior season vaccination on current season vaccine effectiveness
- The recommendations of the Advisory Committee on Immunization Practices for annual influenza vaccination
Age-Specific Considerations
- For older adults (≥65 years), high initial vaccine effectiveness and slow waning suggests that in early-peaking seasons, early vaccination most effectively reduces disease burden, while in late-peaking seasons delaying vaccination is most effective 2.
- For children who need 2 doses, the first dose should be received as soon as possible after vaccine becomes available to allow the second dose to be received by the end of October 3.