AbstractObjectives:Healthcare workers (HCWs) are a high-priority group for coronavirus disease 2019 (COVID-19) vaccination and serve as sources for public information. In this analysis, we assessed vaccine intentions, factors associated with intentions, and change in uptake over time in HCWs.Methods:A prospective cohort study of COVID-19 seroprevalence was conducted with HCWs in a large healthcare system in the Chicago area. Participants completed surveys from November 25, 2020, to January 9, 2021, and from April 24 to July 12, 2021, on COVID-19 exposures, diagnosis and symptoms, demographics, and vaccination status.Results:Of 4,180 HCWs who responded to a survey, 77.1% indicated that they intended to get the vaccine. In this group, 23.2% had already received at least 1 dose of the vaccine, 17.4% were unsure, and 5.5% reported that they would not get the vaccine. Factors associated with intention or vaccination were being exposed to clinical procedures (vs no procedures: adjusted odds ratio [AOR], 1.39; 95% confidence interval [CI], 1.16–1.65) and having a negative serology test for COVID-19 (vs no test: AOR, 1.46; 95% CI, 1.24–1.73). Nurses (vs physicians: AOR, 0.24; 95% CI, 0.17–0.33), non-Hispanic Black (vs Asians: AOR, 0.35; 95% CI, 0.21–0.59), and women (vs men: AOR, 0.38; 95% CI, 0.30–0.50) had lower odds of intention to get vaccinated. By 6-months follow-up, >90% of those who had previously been unsure were vaccinated, whereas 59.7% of those who previously reported no intention of getting vaccinated, were vaccinated.Conclusions:COVID-19 vaccination in HCWs was high, but variability in vaccination intention exists. Targeted messaging coupled with vaccine mandates can support uptake.