SARS-CoV-2 environmental contamination from hospitalised patients with COVID-19 receiving aerosol-generating procedures

Abstract

BackgroundContinuous positive airways pressure (CPAP) and high-flow nasal oxygen (HFNO) are considered ‘aerosol-generating procedures’ in the treatment of COVID-19.ObjectiveTo measure air and surface environmental contamination with SARS-CoV-2 virus when CPAP and HFNO are used, compared with supplemental oxygen, to investigate the potential risks of viral transmission to healthcare workers and patients.Methods30 hospitalised patients with COVID-19 requiring supplemental oxygen, with a fraction of inspired oxygen ≥0.4 to maintain oxygen saturation ≥94%, were prospectively enrolled into an observational environmental sampling study. Participants received either supplemental oxygen, CPAP or HFNO (n=10 in each group). A nasopharyngeal swab, three air and three surface samples were collected from each participant and the clinical environment. Real-time quantitative polymerase chain reaction analyses were performed for viral and human RNA, and positive/suspected-positive samples were cultured for the presence of biologically viable virus.ResultsOverall 21/30 (70%) participants tested positive for SARS-CoV-2 RNA in the nasopharynx. In contrast, only 4/90 (4%) and 6/90 (7%) of all air and surface samples tested positive (positive for E and ORF1a) for viral RNA respectively, although there were an additional 10 suspected-positive samples in both air and surfaces samples (positive for E or ORF1a). CPAP/HFNO use or coughing was not associated with significantly more environmental contamination than supplemental oxygen use. Only one nasopharyngeal sample was culture positive.ConclusionsThe use of CPAP and HFNO to treat moderate/severe COVID-19 did not appear to be associated with substantially higher levels of air or surface viral contamination in the immediate care environment, compared with the use of supplemental oxygen.

Revisiting SARS-CoV-2 environmental contamination by patients with COVID-19: The Omicron variant does not differ from previous strains

“…Our results demonstrate that in terms of contamination, viability and stability on surfaces and in air samples, the Omicron variant is remarkably similar to previous Covid-19 strains (original and Alpha strains). This correlates with previous studies conducted by us (Ben-Shmuel et al, 2020) and others (Lane et al, 2021;Ong et al, 2021;Thakar et al, 2021;Winslow et al, 2021) in health-care settings, isolation units, quarantine hotels and schools. Moreover, it was recently demonstrated that SARS-CoV-2 significantly loses viability, with near complete viability loss occurring within 2-5 minutes, in controlled laboratory aerosolized dispersion at normal relative humidity (Oswin et al, 2022).…”

Aerosol-Generating Procedures and Virus Transmission

“…50 Winslow and colleagues measured air and surface environmental contamination with SARS-CoV-2 virus in the room of subjects who received CPAP or HFNC treatment. 51 Compared to those subjects who used conventional oxygen therapy, they did not find any significant differences in the groups receiving CPAP or HFNC treatments. 51 Likewise, Thuresson et al found that the number of positive air samples with SARS-CoV-2 detection was similar in subjects treated with versus without respiratory support (HFNC or NIV).…”

Update June 2022: management of hospitalised adults with coronavirus disease 2019 (COVID-19): a European Respiratory Society living guideline

“…An open feasibility study showed that delivery of both HFNO and CPAP can be safely carried out in a HDU in patients with a single organ failure. Ongoing studies suggest that with the use of modified circuits and PPE, dissemination of the infection from CPAP and HFNO devices may be low and ultimately risks depend on the infectivity of patient and specific manoeuvres [143][144][145] .…”

“…The nature of aerosol generation or dispersion when using CPAP and HFNO has been explored using a range of imaging, particle sizing and virus sampling studies, producing mixed results. [143][144][145] Benefits of CPAP and HFNO should be balanced against risks.…”