Coronaviruses have been implicated in nosocomial outbreaks 1 with environmental contamination as a route of transmission. 2 Similarly, nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported. 3 However, the mode of transmission and extent of environmental contamination are unknown.Methods | From January 24 to February 4, 2020, 3 patients at the dedicated SARS-CoV-2 outbreak center in Singapore in airborne infection isolation rooms (12 air exchanges per hour) with anterooms and bathrooms had surface environmental samples taken at 26 sites. Personal protective equipment (PPE) samples from study physicians exiting the patient rooms also were collected. Sterile premoistened swabs were used.Air sampling was done on 2 days using SKC Universal pumps (with 37-mm filter cassettes and 0.3-μm polytetrafluoroethylene filters for 4 hours at 5 L/min) in the room and anteroom and a Sartorius MD8 microbiological sampler (with gelatin membrane filter for 15 minutes at 6 m 3 /h) outside the room (eFigure in the Supplement).Specific real-time reverse transcriptase-polymerase chain reaction (RT-PCR) targeting RNA-dependent RNA polymerase and E genes 4 was used to detect the presence of SARS-CoV-2 (see detailed methods in the eAppendix in the Supplement). Cycle threshold values, ie, number of cycles required for the fluorescent signal to cross the threshold in RT-PCR, quantified viral load, with lower values indicating higher viral load.

Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. Here we screen surface and air samples from hospital rooms of COVID-19 patients for SARS-CoV-2 RNA. Environmental sampling is conducted in three airborne infection isolation rooms (AIIRs) in the ICU and 27 AIIRs in the general ward. 245 surface samples are collected. 56.7% of rooms have at least one environmental surface contaminated. High touch surface contamination is shown in ten (66.7%) out of 15 patients in the first week of illness, and three (20%) beyond the first week of illness (p = 0.01, χ2 test). Air sampling is performed in three of the 27 AIIRs in the general ward, and detects SARS-CoV-2 PCR-positive particles of sizes >4 µm and 1–4 µm in two rooms, despite these rooms having 12 air changes per hour. This warrants further study of the airborne transmission potential of SARS-CoV-2.

No abstract

No abstract

Background: The risk of environmental contamination by SARS-CoV-2 in the intensive care unit (ICU) is unclear. We aimed to evaluate the extent of environmental contamination in the ICU and correlate this with patient and disease factors, including the impact of different ventilatory modalities. Methods: Observational study where surface environmental samples collected from ICU patient rooms and common areas were tested by SARS-CoV-2 PCR, with select samples from the common area tested on cell culture. Clinical data were collected and correlated to presence of environmental contamination. Results were compared to historical data from a previous study in general wards (GW). Results: 200 samples from 20 patient rooms, and 75 samples from common areas and the staff pantry, were tested. 14 rooms had at least one site contaminated, with an overall contamination rate of 14% (28 of 200 samples). Environmental contamination was not associated with day of illness, ventilatory mode, aerosol generating procedures, or viral load. There was lower frequency of environmental contamination in ICU compared to GW rooms. Eight samples from the common area were positive, though all were negative on cell culture. Conclusion: Environmental contamination in the ICU is lower compared to the GW. Use of mechanical ventilation or high-flow nasal oxygen was not associated with greater surface contamination, supporting their use and safety from an infection control perspective. Transmission risk via environmental surfaces in the ICUs is likely to be low. Nonetheless, infection control practices should be strictly reinforced, and transmission risk via droplet or airborne spread remains.