Study looks into COVID-19 surface contamination

A new study published in the Infection Control & Hospital Epidemiology journal looked into possible associations between surfaces contaminated with SARS-CoV-2 and health care worker COVID-19 infection rates. 

The study was conducted from September 2020 to January 2021 at the Hospital of the University of Pennsylvania in Philadelphia. Surface samples were collected weekly from staff breakrooms and bathrooms, and nurse workstations in four patient care areas: a medical ward, an intensive care unit (ICU) for COVID-19 care and two nondedicated ICUs. 

Samples specifically were collected from high-touch surfaces such as refrigerator handles, microwave handles and tables; staff bathroom surfaces, comprising toilets, sinks and doorknobs; and floors. Weekly sampling also was performed in nurse workstations on computer mice and floors. 

In total, 640 samples were obtained from staff common areas over the 20-week study time frame, during which there were 18 incidents of SARS-CoV-2 infections among the study unit nursing staff. Sources of infection included patient exposure (1), unspecified workplace exposure (2), community exposure (1) and unknown (14).

Researchers detected a borderline significant association between increased relative incidence of health care worker infection with increasing common area surface contamination. Although the numbers were no longer statistically significant after being adjusted for community incidence, the study authors say the data provide key insights. 

“Common area surface contamination did not predict health care worker COVID-19 [infection rates] after adjusting for community incidence,” the study authors wrote. 

“However, increased surface contamination was observed as the COVID-19 patient census increased over time, underscoring a need to ensure adequate staffing, resources and efforts for environmental disinfection,” the researchers added.