Do aspirating systems have a role in preventing COVID-19 transmission among dental healthcare workers?

Aim The aim of this retrospective cohort study was to determine and compare the seropositivity rates of SARS-CoV-2 among dental healthcare workers (HCWs) working in three different clinics using different types of aspirating systems. The study took place in Ekaterinburg (Russian Federation). Methods A total of 157 HCWs from three different clinics (56, 60 and 41 HCWs, respectively) who worked during the COVID-19 pandemic period (May to August 2020) constituted the cohort. All of the three chosen clinics had followed COVID-19 screening, triage and other recommendations for safe practice. In addition to using personal protective equipment and other common barrier methods to lower virus transmission, these clinics were equipped with different types of aspirating systems that included V6000 used in dry mode, V6000 used in semi-dry mode and VS900, respectively. All HCWs underwent serological testing once a week to detect immunoglobulin G and M antibodies against SARS-CoV-2 using SARS-CoV-2-IgG-EIA-BEST and SARS-CoV-2-IgM-EIA-BEST enzyme immunoassay kits (Vector-Best). Results An overall prevalence of seropositivity was observed to be 11.5% (19/157 HCWs) over a five-month follow-up. The prevalence of infection was not found to be associated with sex or the role of the member in the dental team (dentist/dental assistant). Significantly higher infection rates (p <0.001) were observed among HCWs working in the clinic equipped with the VS900 aspirating vacuum pump without HEPA filters, while the lowest infection rate was found among HCWs working in the clinic using the V6000 aspirating system in dry mode. Conclusions HCWs working in the clinic equipped with an aspirating system which has HEPA filters and released the air into an external environment (V6000) exhibited significantly lower seroprevalence rates compared to HCWs in the clinic using an aspirating system without HEPA filters which released air within the dental operatory away from the operation site (VS900).