State COVID-19 Vaccine Mandates and Uptake Among Health Care Workers in the US.

Importance: Seventeen states introduced COVID-19 vaccine mandates for health care workers (HCWs) in mid-2021. Prior research on the effect of these mandates was centered on the nursing home sector, and more evidence is needed for their effect on the entire HCW population. Objective: To examine the association between state COVID-19 vaccine mandates for HCWs and vaccine uptake in this population. Design, Setting, and Participants: This repeated cross-sectional study included biweekly, individual-level data for adults aged 25 to 64 years who were working or volunteering in health care settings obtained from the Household Pulse Survey between May 26 and October 11, 2021. Analyses were conducted between November 2022 and October 2023. Exposure: Announcement of a state COVID-19 vaccine mandate for HCWs. Main Outcomes and Measures: An indicator for whether a sampled HCW ever received a COVID-19 vaccine and an indicator for whether an HCW completed or intended to complete the primary COVID-19 vaccination series. Event study analyses using staggered difference-in-differences methods compared vaccine uptake among HCWs in mandate and nonmandate states before and after each mandate announcement. The sample was further stratified by the availability of regular COVID-19 testing in place of a vaccination (ie, a test-out option) and by the ages of HCWs (25-49 or 50-64 years) to examine heterogeneous associations. Results: The study sample included 31 142 HCWs (mean [SD] age, 45.5 [10.6] years; 72.1% female) from 45 states, 16 of which introduced COVID-19 vaccine mandates for HCWs. Results indicated a mandate-associated 3.46-percentage point (pp) (95% CI, 0.29-6.63 pp; P = .03) increase in the proportion of HCWs ever vaccinated against COVID-19 and a 3.64-pp (95% CI, 0.72-6.57 pp; P = .02) increase in the proportion that completed or intended to complete the primary vaccination series 2 weeks after mandate announcement from baseline proportions of 87.98% and 86.12%, respectively. In the stratified analyses, positive associations were only detected in mandate states with no test-out option and among HCWs aged 25 to 49 years, which suggested vaccination increases of 3.32% to 7.09% compared with baseline proportions. Conclusions and Relevance: This repeated cross-sectional study found that state COVID-19 vaccine mandates for HCWs were associated with increased vaccine uptake among HCWs, especially among younger HCWs and those in states with no test-out option. These findings suggest the potential for vaccine mandates to further promote vaccinations in an already highly vaccinated HCW population, especially when no test-out option is in place.