Occupational COVID-19 risk to dental staff working in a public dental unit in the outbreak epicenter

Objective: The management of the COVID-19 outbreak occurred in Lombardy (Italy) implied that non-COVID-19 health care was remodeled, limiting adequate resources in non-hospital public dental healthcare settings. This situation offered the opportunity to investigate the occupational COVID-19 risk to dental staff in public non-hospital dental units. Methods: An infection control protocol was designed for dental health care in the Territorial Health and Social Services Authority (ASST) "Melegnano and Martesana" (Milan). Since specific guidance from central authorities was lacking, information was gathered from international public health organizations. The probability to visit asymptomatic COVID-19-infected patients was estimated, and the occupational risk to dental staff was calculated. Results: The probability to visit asymptomatic patients passed from 1.2% (95% confidence interval -95 CI, 0.6%-2.5%) in the first period (20 February-15 March 2020) to 11.1% (95 CI, 5.8%-23.6%) in the second period (16 March-30 April). Dentists and dental assistants did not develop COVID-19, while one nurse did, the nature of her occupational risk was unclear, as nurses provided prevalently non-dental health care. The probabilities of developing COVID-19 per worked hour per person excluding and including this uncertain situation were 0.0% (95 CI, 0.0%-3.2%) and 0.9% (95 CI, 0.1%-4.7%). Conclusion: Relatively simple infection control procedures were enough to control occupational COVID-19 risk during the outbreak.