Air and Environmental Contamination Caused by COVID-19 Patients: a Multi-Center Study

Abstract

Background: The purpose of this study was to determine the extent of air and surface contamination of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in four health care facilities with hospitalized coronavirus disease 2019 (COVID-19) patients.

Methods: We investigated air and environmental contamination in the rooms of eight COVID-19 patients in four hospitals. Some patients were in negative-pressure rooms, and others were not. None had undergone aerosol-generating procedures. On days 0, 3, 5, and 7 of hospitalization, the surfaces in the rooms and anterooms were swabbed, and air samples were collected 2 m from the patient and from the anterooms.

Results: All 52 air samples were negative for SARS-CoV-2 RNA. Widespread surface contamination of SARS-CoV-2 RNA was observed. In total, 89 of 320 (27%) environmental surface samples were positive for SARS-CoV-2 RNA. Surface contamination of SARS-CoV-2 RNA was common in rooms without surface disinfection and in rooms sprayed with disinfectant twice a day. However, SARS-CoV-2 RNA was not detected in a room cleaned with disinfectant wipes on a regular basis.

Conclusion: Our data suggest that remote (> 2 m) airborne transmission of SARS-CoV-2 from hospitalized COVID-19 patients is uncommon when aerosol-generating procedures have not been performed. Surface contamination was widespread, except in a room routinely cleaned with disinfectant wipes.

Keywords: Droplet; Environmental Sampling; SARS-CoV-2; Transmission.

Fig. 1. Environmental sampling sites and the Ct values of rooms in each hospital are illustrated in dots. Red dot indicates sample with Ct value ≤ 35 in real-time polymerase chain reaction; orange dot indicates sample with Ct value > 35 and ≤ 40; green dot indicates sample with negative result. Two AIIRs in Hospital A (A) and an AIIR in Hospital B (B). Two non-AIIRs in Hospital C (C) and a cohort non-AIIR in Hospital D (D).

Ct = cycle threshold, AIIR = airborne infection isolation room, Hospital A = Chonnam National University Hospital, Hospital B = Chonnam National University Hwasun Hospital, Hospital C = Chonnam National University Bitgoeul Hospital, Hospital D = Keimyung University Daegu Dongsan Hospital.