Influenza vaccine effectiveness against medically attended outpatient illness, United States, 2023-24 season.

ABSTRACT:

Background

The 2023-24 U.S. influenza season was characterized by a predominance of A(H1N1)pdm09 virus circulation with co-circulation of A(H3N2) and B/Victoria viruses. We estimated vaccine effectiveness (VE) in the United States against mild-to-moderate medically attended influenza illness in the 2023-24 season.

Methods

We enrolled outpatients aged ≥8 months with acute respiratory illness in 7 states. Respiratory specimens were tested for influenza type/subtype by reverse-transcriptase polymerase chain reaction (RT-PCR). Influenza VE was estimated with a test-negative design comparing odds of testing positive for influenza among vaccinated versus unvaccinated participants. We estimated VE by virus sub-type/lineage and A(H1N1)pdm09 genetic subclades.

Results

Among 6,

SUBMITTER: Chung JR 

PROVIDER: S-EPMC12287938 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature