COVID-19 in hospitals: Toilets, staff, public areas show contamination

Pearl Toh
28 Sep 2020

With a great deal of controversy surrounding the possible transmission route of SARS-CoV-2 virus, a study reveals yet another surprise worthy of caution in the hospital setting.

The review study, presented during the ESCMID* Conference on Coronavirus Disease (ECCVID), showed high level of viral load in the air surrounding COVID-19 patients, toilets, as well as staff and public areas in hospitals. [ECCVID 2020, abstract 00757]

Based on 17 papers included in the review, more than a quarter (27.5 percent) of the air sampled from enclosed hospital environment around COVID-19 patients tested positive for SARS-CoV-2 RNA, regardless of whether it was in the intense care unit (ICU; 27/97, 27.8 percent) or non-ICU settings (41/150, 27.3 percent).

Of the 67 air samples collected less than 1 metre away from the patient, only one (1.5 percent) turned out positive SARS-CoV-2. For air sampled at a distance of 1–5 metres away from the cases, 6 percent (4/67) were positive for SARS-CoV-2.

This implies few infectivity of the air surrounding patients with COVID-19, according to Dr Gabriel Birgand, University Hospital Centre Nantes, France.

However, in other areas within the hospitals such as patient toilets, the rate of positivity for SARS-CoV-2 was 23.8 percent of the 21 toilets tested, and hit as high as 34.1 percent (14/41) in public areas in hospital settings.

Of note, the median SARS-CoV-2 RNA concentration in patient toilets was 10 times higher than the samples collected from the patients’ rooms.  

For staff areas and clinical sites, SARS-CoV-2 contamination was found in 15 of 121 samples (12.4 percent) and 20 of 221 samples (9.5 percent), respectively.

As detection of SARS-CoV-2 RNA does not necessarily mean the virus is viable, the researchers also compared results of viral cultures from these areas.

Among the 78 viral cultures performed, three showed viable SARS-CoV-2 virus (4 percent) — with all of these sourced from enclosed patient environments in non-ICU settings (3/39, 7.7 percent).

“In hospital, the air near COVID-19 patients is frequently contaminated with SARS-CoV-2 RNA, with however, poor proof of its infectivity — meaning we detected the viral RNA, but when trying to culture these samples, there was little evidence of viable virus,” pointed out Birgand.

“High viral loads found in toilet/bathrooms, staff and public hallways means these areas require strong compliance with cleaning measures and personal protective equipment [PPE],” he added.

As Birgand explained, these findings support the current recommendations for PPE — that surgical facemask is efficient for preventing transmission from patient to healthcare workers in most settings, except in aerosol generating procedures whereby protection class respirators FFP2 are required.

For the review study, Birgand and team identified 2,034 published literature on air contamination by COVID-19 in the hospital settings — of which, 17 met the eligibility criteria for inclusion. The contamination rate indicated by SARS-CoV-2 viral RNA was compared across different hospital settings, clinical context, distance from patient, and air ventilation system.

The study also corroborates what was observed previously in environmental sampling from three hospital rooms of COVID-19 patients in National Centre for Infectious Diseases, Singapore, which showed contamination in toilet bowls and air exhaust outlets. Samples taken after disinfection measures turned out negative, which highlights the importance of routine cleaning. [JAMA 2020;323:1610-1612]

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