Risk of SARS-CoV-2 infection in dental healthcare workers - a systematic review and meta-analysis

Background: Mounting evidence supports an association between the use of personal protective equipment (PPE) and the risk of infection from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) in dental healthcare workers (DCW). However, the prevalence and incidence of SARS-CoV-2 infections in the setting of dental care remains poorly characterized. Methods: A systematic review and meta -analysis of studies published prior to Mai 2023 providing epidemiological data for the occurrence of SARS-CoV-2 in DCW was performed. A random -effects model was used to calculate pooled estimates and odds ratios (ORs) with corresponding 95% confidence intervals (CIs). The associated factors were narratively evaluated. Risk of bias was assessed using the Joanna Briggs Institute tool for prevalence studies. Results: Twenty-nine eligible studies were identified including a total of 85,274 DCW at risk; 27 studies met the criteria for the meta -analysis. Among the included DCW, the overall prevalence of SARS-CoV-2 was 11.8% (13,155/85,274; 95%CI, 7.5%-17%), whereby the degree of heterogeneity between the studies was considerable (I-2=99.7%). The pooled prevalence rate for dentists and dental hygienists alone was 12.7% (1943/20,860; 95%CI, 8.0%-18.0%), showing significantly increased odds of contracting a SARS-CoV-2 infection compared to dental assistant personnel, the prevalence rate for which was less than half, at 5.2% (613/15,066; OR=2.42; 95% CI, 2.2-2.7). In the subgroup of 17 studies from countries with high income there was a significantly lower prevalence rate of 7.3% (95% CI, 5%-10%) in DCW compared to the prevalence rate in low- and middle -income countries, which came to 20.8% (95% CI, 14%-29%; p<0.001). In 19 out of the 29 studies (65.5%), specific information on the use of and adherence to PPE was absent while in the reports with concrete figures the wearing of N95 (or at least surgical masks) by DCW appeared to be associated with lower SARS-CoV-2 prevalence rates. Conclusions: DCW were, depending in each case on their proximity to patients, at particular risk of SARS-CoV-2 infection during the COVID-19 pandemic. Until a significant level of vaccination protection against newer SARS-CoV-2 variants can be built up in the population, dental healthcare facilities should further maintain their focus on using PPE according to current guidelines.