Breakthrough COVID-19 Infections Among Healthcare Workers at a Tertiary Care Hospital in Beirut: Prevalence and Determinants

• Higher number of vaccine doses were associated with fewer breakthrough infections. • Nausea/vomiting were less frequent among HCWs with breakthrough infections. • Findings support boosters and higher HCW vaccine coverage. : Despite mass vaccination campaigns to limit the spread of COVID-19, breakthrough infections have been reported in many countries. This raises a global concern on the longevity and scope of vaccine-induced immunity, especially among high-risk population such as Healthcare Workers (HCWs). This study aims to examine the prevalence and predictors of breakthrough infections among HCWs at a tertiary care hospital in Beirut. : A cross-sectional study was conducted among 300 HCWs from clinical and non-clinical departments. Data was collected using a structured questionnaire assessing demographics, vaccination, COVID-19 exposure, compliance to preventive measures, symptoms and clinical outcomes with bivariate and multivariate analysis. The data were collected from participants between November and December 2023 : Of the 300 HCWs, 36.5% (n=46) had breakthrough infections. In multivariate analysis, receiving more vaccine doses was associated with reduced odds of breakthrough infection (OR = 0.315, 95% CI: 0.116-0.855, p=0.023). No significant associations were found with age, comorbidities, work area, number of exposures, and compliance with preventive regulations. : Receiving more COVID-19 vaccine doses was significantly associated with reduced likelihood of breakthrough infection among HCWs. These findings emphasize the importance of booster vaccination and support continued efforts to promote full vaccine coverage within healthcare settings.