Seasonal Influenza Prevention & Control

“Preliminary estimates indicate that influenza levels rose during the 2021-2022 season, though still lower than most previous pre-pandemic years, and there is potential for a more severe season coming up.” 
- Pamela Rockwell, D.O., AAFP’s liaison to the ACIP. 
 

Influenza Vaccine Updates

Routine annual influenza vaccination of all persons aged ≥6 months who do not have contraindications continues to be recommended. Primary updates in this report include the following:

1. The composition of the 2022–23 U.S. seasonal influenza vaccines includes updates to the influenza A(H3N2) and influenza B/Victoria components. For the 2022–23 season, U.S.-licensed influenza vaccines will contain hemagglutinin (HA) derived from an influenza A/Victoria/2570/2019 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/588/2019 (H1N1)pdm09-like virus (for cell culture–based and recombinant vaccines); an influenza A/Darwin/9/2021 (H3N2)-like virus (for egg-based vaccines) or an influenza A/Darwin/6/2021 (H3N2)-like virus (for cell culture–based or recombinant vaccines); an influenza B/Austria/1359417/2021 (Victoria lineage)-like virus; and an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus.
2. Influenza vaccines expected to be available for the 2022–23 season, their age indications, and their presentations are described (Table 1). Afluria Quadrivalent is not expected to be available in a 0.25-mL prefilled syringe presentation. When using Afluria Quadrivalent for children aged 6 through 35 months (who require a 0.25-mL dose), the dose must be obtained from a multidose vial. One labeling change is described. In October 2021, FDA granted approval for the use of Flucelvax Quadrivalent (cell culture–based quadrivalent inactivated influenza vaccine [ccIIV4]) for children aged 6 months through <2 years. As of March 2021, Flucelvax Quadrivalent had been approved for persons aged ≥2 years. Approval for children aged 6 months through <2 years was based on results of a randomized, observer-blind study that compared immunogenicity and safety of Flucelvax Quadrivalent with that of a licensed comparator IIV4 among 2,402 children aged 6 through 47 months, of whom 894 were aged 6 through 23 months. Flucelvax Quadrivalent is now approved for persons aged ≥6 months.
3. On the basis of review of evidence concerning high-dose inactivated influenza vaccine (HD-IIV), recombinant influenza vaccine (RIV), and MF59-adjuvanted inactivated influenza vaccine (aIIV), recommendations for influenza vaccination of persons aged ≥65 years have been modified. ACIP recommends that adults aged ≥65 years preferentially receive any one of the following higher dose or adjuvanted influenza vaccines: quadrivalent high-dose inactivated influenza vaccine (HD-IIV4), quadrivalent recombinant influenza vaccine (RIV4), or quadrivalent adjuvanted inactivated influenza vaccine (aIIV4). If none of these three vaccines is available at an opportunity for vaccine administration, then any other age-appropriate influenza vaccine should be used. Higher dose vaccines include HD-IIV4 and RIV4, both of which contain a higher dose of HA antigen per virus than standard-dose vaccines (60 µg for HD-IIV4 and 45 µg for RIV4, compared with 15 µg for standard-dose inactivated vaccines). Adjuvanted inactivated influenza vaccine (aIIV4) contains MF59 adjuvant.
    

Influenza Vaccine Additional Recommendations

Populations at Higher Risk for Medical Complications Attributable to Severe Influenza

All persons aged ≥6 months who do not have contraindications should be vaccinated annually. However, vaccination to prevent influenza is particularly important for persons who are at increased risk for severe illness and complications from influenza and for influenza-related outpatient, emergency department, or hospital visits. When vaccine supply is limited, vaccination efforts should focus on vaccination of persons at higher risk for medical complications attributable to severe influenza who do not have contraindications. These persons include the following (no hierarchy is implied by order of listing):

• All children aged 6 through 59 months.
• All persons aged ≥50 years.
• Adults and children who have chronic pulmonary (including asthma), cardiovascular (excluding isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus).
• Persons who are immunocompromised due to any cause (including but not limited to immunosuppression caused by medications or HIV infection).
• Persons who are or will be pregnant during the influenza season.
• Children and adolescents (aged 6 months through 18 years) who are receiving aspirin- or salicylate-containing medications and who might be at risk for experiencing Reye syndrome after influenza virus infection.
• Residents of nursing homes and other long-term care facilities.
• American Indian or Alaska Native persons.
• Persons who are extremely obese (body mass index ≥40 for adults).
   

Immunization Resources