Pregnancy and Influenza Vaccination Behavior in the United States

Objectives. To estimate the influence of pregnancy on influenza vaccination before, during, and after pregnancy across the 2017-2018 to 2021-2022 influenza seasons in the United States. Methods. Using Optum's de-identified Clinformatics Data Mart Database, we conducted a retrospective cohort study examining influenza vaccination uptake among pregnant individuals before, during, and after their pregnancies. We used difference-in-differences analyses to assess changes in the pregnancy and postpregnancy effects across influenza seasons. Results. Influenza vaccination uptake was highest during pregnancy (44.6%), compared with the before- (27.6%) and after-pregnancy cohorts (30.1%). Pregnant individuals had more than twice the odds of vaccination during pregnancy compared with before pregnancy (adjusted odds ratio [AOR] = 2.3; 95% confidence interval [CI] = 2.26, 2.33). The postpregnancy effect was modest (AOR = 1.17; 95% CI = 1.15, 1.19). Both pregnancy and postpregnancy effects decreased after the onset of the COVID-19 pandemic. Conclusions. Influenza vaccination uptake was higher during pregnancy but decreased after delivery in the United States. Pregnancy is a key opportunity to promote immunization through prenatal care. Strengthening provider engagement and extending vaccine recommendations into the postpregnancy period may help sustain vaccination uptake. (Am J Public Health. Published online ahead of print October 22, 2026:e1-e10. https://doi.org/10.2105/AJPH.2026.308636).