SARS‐CoV‐2 indoor environment contamination with epidemiological and experimental investigations

Abstract

SARS‐CoV‐2 has been detected both in air and on surfaces, but questions remain about the patient‐specific and environmental factors affecting virus transmission. Additionally, more detailed information on viral sampling of the air is needed. This prospective cohort study (N = 56) presents results from 258 air and 252 surface samples from the surroundings of 23 hospitalized and eight home‐treated COVID‐19 index patients between July 2020 and March 2021 and compares the results between the measured environments and patient factors. Additionally, epidemiological and experimental investigations were performed. The proportions of qRT‐PCR‐positive air (10.7% hospital/17.6% homes) and surface samples (8.8%/12.9%) showed statistical similarity in hospital and homes. Significant SARS‐CoV‐2 air contamination was observed in a large (655.25 m3) mechanically ventilated (1.67 air changes per hour, 32.4–421 L/s/patient) patient hall even with only two patients present. All positive air samples were obtained in the absence of aerosol‐generating procedures. In four cases, positive environmental samples were detected after the patients had developed a neutralizing IgG response. SARS‐CoV‐2 RNA was detected in the following particle sizes: 0.65–4.7 μm, 7.0–12.0 μm, >10 μm, and <100 μm. Appropriate infection control against airborne and surface transmission routes is needed in both environments, even after antibody production has begun.

Detection of hospital environmental contamination during SARS-CoV-2 Omicron predominance using a highly sensitive air sampling device

“…Additionally, the high flow rate of 200 L/min allows detection in short time frames. These features are a combination of the individual strengths of different sampling methods reported in previous studies and highlights the utility of the device we tested (18,42,43). In addition, findings of long-distance aerial dispersal have been reported (43,44), which further affirms the utility of this device for long-range detection.…”

“…These features are a combination of the individual strengths of different sampling methods reported in previous studies and highlights the utility of the device we tested (18,42,43). In addition, findings of long-distance aerial dispersal have been reported (43,44), which further affirms the utility of this device for long-range detection. Furthermore, the device we employed utilized liquid-coated collection substrates, which can improve the retrieval rate of airborne pathogens such as SARS-CoV-2 (45).…”

Combining Phi6 as a surrogate virus and computational large‐eddy simulations to study airborne transmission of SARS‐CoV‐2 in a restaurant

“…Thus, our method for producing the aerosol particles was relevant for the respiratory context. Most of the respiratory pathogens, including also SARS‐CoV‐2, are found in particles smaller than 5 μm 11,46–48 . These small aerosol particles can remain airborne for a long time, accumulate indoors, travel with air currents as seen in our results, and can deposit in the lungs when inhaled 49–51 .…”

“…Most of the respiratory pathogens, including also SARS-CoV-2, are found in particles smaller than 5 μm. 11,[46][47][48] These small aerosol particles can remain airborne for a long time, accumulate indoors, travel with air currents as seen in our results, and can deposit in the lungs when inhaled. [49][50][51] Furthermore, aerosol inoculations have been associated with more severe infection pathology even when caused by a lower viral dose compared to transmissions via other routes.…”

“…As can be expected, the highest positivity rates from air samples have been close to a known source of infection 6 . Additionally, SARS‐CoV‐2 has been detected in multiple air samples, in multiple particle sizes with an emphasis on small aerosols 7–12 . After a wide scientific discussion during the pandemic, there is a strengthening consensus that SARS‐CoV‐2 spreads mainly by both short and long‐distance airborne transmission via infective aerosol particles 13–19 .…”