Effectiveness of SARS-CoV-2 Vaccination Among Health Care Workers

Research published in Vaccine: X provides a comprehensive analysis of the effectiveness of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in health care workers, showing high levels of protection against infection, symptomatic infection, and hospitalization, with some evidence of waning protection over time.

SARS-CoV-2 vaccination has been highly effective in preventing infection and severe disease, although rates of illness and reinfections remain high due to factors such as waning immunity and new virus variants. Health care workers, who have been prioritized for vaccination, are an ideal group to study the relationship between SARS-CoV-2 infection and vaccination because of easy access to testing and diagnostics.

A search was conducted in Ovid MEDLINE and Embase using various terms related to COVID-19 vaccination and health care workers. The search terms were selected based on previous exploratory searches and literature reviews. Studies were independently evaluated for inclusion based on criteria such as vaccine effectiveness against infection in health care workers, focusing on outcomes such as symptomatic infection, hospitalization, and death.

Most participants were women of working age, with a median time to infection of 51 days. Vaccine effectiveness ranged from 5% to 100% against infection, 34% to 100% against symptomatic infection, and 65% to 100% against infection requiring hospitalization. No vaccinated health care worker deaths were reported in any study. Pooled estimates showed protection rates of 84.7% against infection, 86.0% against symptomatic infection, and 96.1% against hospitalization, with some studies showing waning protection against infection but continued protection against severe infection for at least 6 months after vaccination.

“Waning protection is reported but this awaits more mature studies to understand durability more clearly,” researchers said. “This study is limited by varying non-pharmacological responses to COVID-19 between included studies, a predominantly female and working age population, and limited information on asymptomatic transmission or long COVID protection.” 

Reference
Galgut O, Ashford F, Deeks A, et al. COVID-19 vaccines are effective at preventing symptomatic and severe infection among healthcare workers: A clinical review. Vaccine X. 2024;20:100546. doi:10.1016/j.jvacx.2024.100546.