Estimate of airborne transmission of SARS-CoV-2 using real time tracking of health care workers.

Hota, B.; Stein, B.; Lin, M.; Tomich, A.; Segreti, J.; Weinstein, R. A.

BACKGROUND: Whether and to what degree SARS-CoV-2 is spread via the airborne route is unknown. Using data collected from health care worker interactions with hospitalized patients with COVID-19 illness, we calculated the transmissibility of SARS-CoV-2 via the airborne route. OBJECTIVES/METHODS: Healthcare worker interaction with SARS-CoV-2 infected patients were tracked using a real time location system between March 18 and March 31. A value for q, the transmissibility expressed as quanta per hour, was estimated using a well-established model for airborne transmission. RESULTS: SARS-CoV-2 infection prevalence among tracked HCWs was 2.21% (0.07-4.35). Transmissibility was estimated to be 0.225 quanta per hour, well below other well-characterized airborne pathogens. Simulations demonstrated that risk of infection is substantially reduced with increased ventilation of rooms. CONCLUSIONS: Overall, our findings suggest that SARS-CoV-2 is not well transmitted via the airborne route in controlled conditions. We speculate that SARS-CoV-2 may be only opportunistically airborne, with most transmission occurring via droplet methods.