Influenza Vaccine Recommendations Updated by the U.S. CDC

The U.S. Centers for Disease Control and Prevention (CDC) published a Morbidity and Mortality Weekly Report (MMWR) on August 25, 2023, with updated recommendations of the Advisory Committee on Immunization Practices (ACIP) for the 2023–24 Influenza Season.

The primary updates to this new MMWR include the following two topics: 1) the composition of 2023–24 U.S. seasonal influenza vaccines and 2) updated recommendations regarding influenza vaccination of persons with egg allergy.

First, the composition of 2023–24 U.S. influenza vaccines includes an update to the influenza A(H1N1)pdm09 component. U.S.-licensed influenza vaccines will contain HA derived from:

1) an influenza A/Victoria/4897/2022 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/67/2022 (H1N1)pdm09-like virus (for cell culture-based and recombinant vaccines).

2) 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 and recombinant vaccines).

3) an influenza B/Austria/1359417/2021 (Victoria lineage)-like virus.

4) an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus.

Second, the ACIP recommends that all persons aged ≥6 months with egg allergy should receive an influenza vaccine.

Any influenza vaccine (egg-based or non-egg-based) that is otherwise appropriate for the recipient’s age and health status can be used.

It is no longer recommended that persons with allergic reactions to eggs involving symptoms other than urticaria should be vaccinated in an inpatient or outpatient medical setting supervised by a healthcare provider who can recognize and manage severe allergic reactions if an egg-based vaccine is used.

Egg allergy alone necessitates no additional safety measures for influenza vaccination beyond those recommended for any vaccine recipient, regardless of the severity of a previous reaction to an egg.

Furthermore, all flu shots for 2023-2024 should be administered in settings in which personnel and equipment needed for rapid recognition and treatment of acute hypersensitivity reactions are available.

A summary of these recommendations is posted on this CDC webpage.