Impact of coronavirus disease 2019 (COVID-19) vaccination program on healthcare worker infections in an academic hospital

To the Editor—The third wave of the coronavirus disease 2019 (COVID-19) pandemic resulted in a significant rise in hospitalizations and healthcare worker (HCW) severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infections. After implementing the SARS-CoV-2 vaccination program, despite rising COVID-19 hospitalizations, we promptly observed a decrease in HCW infections.

Our COVID-19 vaccination HCW program began on December 16, 2020, (Pfizer/BioNTech) and December 28, 2020 (Moderna). The COVID-19 cases were identified by nasal swab PCR testing of clinically symptomatic individuals. Six days after beginning employee immunizations, our HCW COVID-19 infection rate decreased by 25%. After 60% of employees received the 1st vaccine dose, the HCW COVID-19 rate decreased by 50% (Fig. 1). At 14-28 days and >28 days after their first vaccine dose, HCWs were less likely to have COVID-19 than those who did not receive the vaccine (0.15% and 0.00% vs 0.59%, P = .0002 and .0004, respectively). Concurrently implemented SARS-CoV-2 transmission prevention strategies included the transition from cloth masks to level-3 masks for all employees, mandatory face shields for direct patient care, a restricted visitor policy, and physical space adjustments for improved social distancing.

Fig. 1. Bar graph of 7-day average number of health system employees with positive SARS-CoV-2 tests from November 14, 2020, to January 19, 2021. Yellow dashed line is 7-day average number of COVID-19–positive inpatients over the same period. The black dashed line represents the percentage of total health system employees who received first dose of Pfizer anti–SARS-CoV-2 vaccine, beginning December 16, 2020. The black solid line represents the percentage of total health system employees who received second dose of Pfizer anti-SARS-CoV-2 vaccine, beginning January 6, 2021. Other interventions are as follows: (a) December 14, 2020: reduced adult visitors from 2 to 1; (b) December 21, 2020: required face shields and surgical mask for all patient encounters and restricted cafeteria seating; (c) December 22, 2020: employees to confirm symptom free upon arrival; (d) December 23, 2020: employees to use surgical masks in all areas; (e) December 28, 2020: employee temperature screening on arrival; (f) January 1, 2021: 50% ambulatory visits changes to telehealth; and (g) January 8, 2021: full adult visitor restriction.

The Pfizer/BioNTech clinical trial reported a vaccine efficacy of 95% at least 7 days after the second dose and protection as early as 12 days after administration of the first dose. ² The Moderna vaccine trial observed similar protection prior to the second dose. ³ Our data are consistent with these studies and underscore the prompt benefits of vaccination for the prevention of COVID-19 in the healthcare system even prior to the completion of the second vaccine dose. Our additional infection control strategies are consistent with CDC recommendations ⁴ and likely further optimized HCW safety.

We present a bundled infection prevention approach including vaccination for the prompt reduction of COVID-19 infection in HCWs. The impact of COVID-19 vaccination in HCWs was observed even prior to completion of the second dose. Wood et al ⁵ suggest 12 key strategies to promote vaccination, 2 of which are relevant here: increasing observability and countering anecdotal “bad reaction” with “good reaction” vaccine stories. ⁵ We share our vaccine story to encourage more vaccination-hesitant HCWs to receive immunizations and to receive them earlier. Reaching herd immunity through vaccination is a crucial next step in ending this pandemic.