SARS-CoV-2 RNA and viable virus contamination of hospital emergency department surfaces and association with patient COVID-19 status and aerosol generating procedures

Background: Infectious aerosols and droplets generated by SARS-CoV-2-positive patient aerosol generating procedures (AGPs), coughing, or exhalation could potentially contaminate surfaces, leading to indirect SARS-CoV-2 spread via fomites. Our objective was to determine SARS-CoV-2 surface contamination frequency in Emergency Department (ED) patient rooms with respect to patient SARS-CoV-2 status and AGP receipt. Methods: Swabs were collected from fixed surfaces or equipment in the rooms of patients under investigation for COVID-19 or known to be SARS-CoV-2-positive. Environmental swabs were tested for SARS-CoV-2 RNA by RTqPCR; RNA-positive samples were cultured in Vero E6 cells. Room contamination was also evaluated by clinical severity of COVID-19 and time since symptom onset. Results: In total, 202 rooms were sampled: 42 SARS-CoV-2-positive AGP patient rooms, 45 non-AGP SARS-CoV-2-positive patient rooms, and 115 SARS-CoV-2-negative AGP patient rooms. SARS-CoV-2 RNA was detected on 36 (3.6%) surfaces from 29 (14.4%) rooms. RNA contamination was detected more frequently in rooms occupied by non-AGP SARS-CoV-2-positive patients than SARS-CoV-2-positive AGP patients (28.9% vs 14.3%, p=0.078). Infectious virus was cultured from one non-AGP SARS-CoV-2-positive patient room. There was no significant difference in room positivity according to COVID-19 severity or time since symptom onset. Conclusion: SARS-CoV-2 RNA contamination of ED room surfaces was highest and most frequent in rooms occupied by SARS-CoV-2-positive patients who did not undergo an AGP, which may be attributable to disease stage and viral shedding; however, there was no difference in room contamination according to COVID-19 severity or time since symptom onset.