Investigation of COVID-19 nosocomial infections identifies close contact, not airborne transmission as cause

Editor's Note

This investigation, by researchers at the University of California-Davis Medical Center, of the pattern of transmission of COVID-19 during two nosocomial outbreaks finds that close contact between patients and healthcare workers (HCWs) not airborne transmission was the cause of the outbreak.

Two separate patients were admitted in February and March 2020, without suspicion for COVID-19 and without contact or droplet precautions in place. Both underwent several aerosol generating procedures.

Of 421 HCWs who were exposed by the two patients, investigators identified eight with secondary COVID-19 infections. All eight had close contact with the two index patients without sufficient personal protective equipment. Despite multiple aerosol generating procedures, there was no evidence of airborne transmission.

The findings suggest that a majority of COVID-19 transmissions take place during close contact with infected people through respiratory droplets, rather than long-distance airborne transmissions, the researchers say.