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.

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.

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.

COVID-19 vaccination in HCWs was high, but variability in vaccination intention exists. Targeted messaging coupled with vaccine mandates can support uptake.

To determine the changes in severe acute respiratory coronavirus virus 2 (SARS-CoV-2) serologic status and SARS-CoV-2 infection rates in healthcare workers (HCWs) over 6-months of follow-up.

Prospective cohort study.

HCWs in the Chicago area.

Cohort participants were recruited in May and June 2020 for baseline serology testing (Abbott anti-nucleocapsid IgG) and were then invited for follow-up serology testing 6 months later. Participants completed monthly online surveys that assessed demographics, medical history, coronavirus disease 2019 (COVID-19), and exposures to SARS-CoV-2. The electronic medical record was used to identify SARS-CoV-2 polymerase chain reaction (PCR) positivity during follow-up. Serologic conversion and SARS-CoV-2 infection or possible reinfection rates (cases per 10,000 person days) by antibody status at baseline and follow-up were assessed.

In total, 6,510 HCWs were followed for a total of 1,285,395 person days (median follow-up, 216 days). For participants who had baseline and follow-up serology checked, 285 (6.1%) of the 4,681 seronegative participants at baseline seroconverted to positive at follow-up; 138 (48%) of the 263 who were seropositive at baseline were seronegative at follow-up. When analyzed by baseline serostatus alone, 519 (8.4%) of 6,194 baseline seronegative participants had a positive PCR after baseline serology testing (4.25 per 10,000 person days). Of 316 participants who were seropositive at baseline, 8 (2.5%) met criteria for possible SARS-CoV-2 reinfection (ie, PCR positive >90 days after baseline serology) during follow-up, a rate of 1.27 per 10,000 days at risk. The adjusted rate ratio for possible reinfection in baseline seropositive compared to infection in baseline seronegative participants was 0.26 (95% confidence interval, 0.13–0.53).

Seropositivity in HCWs is associated with moderate protection from future SARS-CoV-2 infection.