The CDC's Advisory Committee on Immunization Practices (ACIP) released updated recommendations for prevention and control of seasonal influenza with vaccines for the 2024-2025 season. The committee recommended annual influenza vaccination for all persons ≥6 months without contraindications.
Key Updates for 2024-2025:
- Trivalent vaccines will be exclusively available, with B/Yamagata omitted due to lack of confirmed detections since March 2020.
- HD-IIV3 and aIIV3 are now acceptable options for solid organ transplant recipients aged 18-64 years on immunosuppressive regimens, without preference over other age-appropriate vaccines.
Vaccine composition:
- Influenza A(H1N1): A/Victoria/4897/2022 (egg-based) or A/Wisconsin/67/2022 (cell culture/recombinant)
- Influenza A(H3N2): A/Thailand/8/2022 (egg-based) or A/Massachusetts/18/2022 (cell culture/recombinant)
- Influenza B: B/Austria/1359417/2021 (Victoria lineage)
For adults ≥65 years, high-dose (HD-IIV3), recombinant (RIV3), or adjuvanted (aIIV3) vaccines were recommended preferentially. Any age-appropriate vaccine should be used if none are available.
Expected vaccines included standard-dose inactivated (IIV3), cell culture-based (ccIIV3), high-dose (HD-IIV3), adjuvanted (aIIV3), recombinant (RIV3), and live attenuated (LAIV3) options.
Vaccination timing: The end of October is recommended but should continue while viruses circulate, and unexpired vaccine remains. Children 6 months–8 years may require 1 or 2 doses depending on prior vaccination. Those needing two doses should receive the first dose as soon as possible, including during July and August.
Egg allergy: Persons with egg allergy of any severity can receive any licensed, recommended influenza vaccine appropriate for their age and health status.
Contraindications and precautions: LAIV3 is contraindicated in immunocompromised persons and pregnant women. Specific timing recommendations exist for LAIV3 administration in relation to antiviral use.
Simultaneous administration: Influenza vaccines can be administered with other vaccines, including COVID-19 vaccines. For vaccines with non-aluminum adjuvants, administration at separate anatomic sites is recommended if given concomitantly.
Travelers: Specific recommendations are provided for travelers to reduce influenza risk.
Storage and handling: Proper temperature requirements and handling procedures are crucial for maintaining vaccine efficacy.
Influenza vaccination impact was substantial. In 2017-2018, vaccination prevented an estimated 7.1 million illnesses, 3.7 million medical visits, 109,000 hospitalizations, and 8,000 deaths, despite 38% effectiveness. Vaccination during pregnancy reduced influenza risk in pregnant/postpartum women and infants <6 months. A meta-analysis found declining effectiveness 4-6 months post-vaccination, with infection odds increasing 9-28% per month overall and 12-29% per month in those ≥65 years.
Enhanced vaccines have improved efficacy in older adults compared to standard-dose in some studies. Extensive data have not shown associations between maternal influenza vaccination and adverse pregnancy outcomes. Severe allergic reactions, while rare, can occur regardless of allergy history. Emergency protocols should be in place at all vaccine administration sites.
Reference:
Grohskopf LA, Ferdinands JM, Blanton LH, Broder KR, Loehr J. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2024–25 Influenza Season. MMWR Recomm Rep 2024;73(No. RR-5):1–25. DOI: http://dx.doi.org/10.15585/mmwr.rr7305a1.
