The U.S. Centers for Disease Control and Prevention (CDC) recently released its preliminary forecast for the 2023-2024 flu season. While the CDC has yet to release its first estimates for the geographic spread of the virus during the upcoming flu season, it has adjusted its annual flu shot recommendations based on the strains of the influenza virus that are expected to be most prevalent over the next year.
Based on its forecast and recommendations from the Advisory Committee on Immunization Practices (ACIP), the CDC has changed the composition of the flu vaccine for the 2023-2024 season. As the CDC explains, “[t]he 2023-2024 season U.S. flu vaccines will contain an updated influenza A(H1N1)pdm09 component.” For the upcoming season, the flu vaccine will be designed to protect against the following strains:
- A/Victoria/4897/2022 (H1N1)pdm09-like virus for egg-based vaccines
- A/Wisconsin/67/2022 (H1N1)pdm09-like virus for cell-based or recombinant vaccines
These are in addition to the strains covered by the 2022-2023 flu vaccine. The carried-over strains are the same for both egg-based and cell-based or recombinant vaccines:
- A/Darwin/6/2021 (H3N2)-like virus;
- B/Austria/1359417/2021 (B/Victoria lineage)-like virus
- B/Phuket/3073/2013 (B/Yamagata lineage)-like virus
The CDC’s Flu Shot Recommendations for the 2023-2024 Flu Season
Notably, even with the addition of the A/Victoria/4897/2022 (H1N1)pdm09-like virus strain for egg-based vaccines, the CDC is advising that individuals who have egg allergies “may receive any flu vaccine (egg-based or non-egg based) that is otherwise appropriate for their age and health status.” This is a change from previous years when the CDC issued additional safety recommendations for flu shot recipients with egg allergies. For the 2023-2024 flu season, the CDC states: “Additional safety measures are no longer recommended for flu vaccination beyond those recommended for receipt of any vaccine.”
The CDC recommends that certain groups of people get the flu shot as early as July, though it notes that September and October are “the best times for most people to get vaccinated.” Based on the CDC’s preliminary forecast, its recommendations for the 2023-2024 flu season include:
- Adults Age 65 and Older – Adults age 65 and older should wait to get vaccinated until September or October unless it isn’t possible to do so.