Subsequent SARS-CoV-2 Infection in Healthcare Workers: A Retrospective Cohort Study in Iran.

BACKGROUND

The evolution of SARS-CoV-2 has increased global COVID-19 case prevalence. Healthcare workers (HCWs) are particularly susceptible to reinfection due to their exposure to infected patients. This study aimed to explore the risk factors for subsequent SARS-CoV-2 infection among HCWs.

METHODS

This retrospective study was conducted in a teaching hospital affiliated with the Iran University of Medical Sciences between March 2021 and October 2021. HCWs completed an online survey to gather information about their COVID-19 infection history. Subsequent SARS-CoV-2 infection was defined as two or more infections, regardless of the time frame interval. Individuals who experienced a second infection within 90 days of the initial infection were considered to have a recurrence, and others were considered to have a reinfection. The generalized estimation equation was utilized to develop a multivariable prediction model.

RESULTS

A total of 601 HCWs (60.2% female), mostly aged 18-29 years (47.4%), participated in this study. We observed 90 episodes of subsequent SARS-CoV-2 infection among HCWs, including 72 individuals (11.98%). Among them, 9 participants (1.5%) experienced recurrence, while 43 participants (7.1%) reported reinfection. In the multivariable analysis, vaccination significantly reduced the risk of subsequent SARS-CoV-2 infection, whereas nurses and those working in COVID-19 wards faced twice the risk.

CONCLUSION

The frequency of subsequent SARS-CoV-2 infection is significant among HCWs. Vaccination status, occupation type, and workplace are key factors influencing the risk of future infections.