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Airborne contamination of COVID-19 in hospitals: a scoping review of the current evidence

Our take —

This study, available as a preprint and thus not yet peer reviewed, provides further evidence that viral RNA can be found in hospital settings, particularly in areas closest to COVID-19 patients, and in bathroom and other public spaces. Less has been shown about the viability of this virus and the potential for airborne transmission. Future studies collecting information on air samples would benefit from providing data on location of sample collection, ventilation systems in place, distance from any positive patients, further clinical context, and viability of virus.

Study design


Study population and setting

The current literature on air contamination in hospital settings was reviewed. Articles published on MEDLINE, Embase, and Web of Science databases between December 1, 2019 and July 21, 2020 were included in the review. The search was augmented to include a review of selected infectious disease journals and certain preprint servers. Data abstraction included key characteristics of the samples (RNA concentrations and particle sizes), the setting and clinical context, the ventilation system, and the methods around sample collection.

Summary of Main Findings

Of the 2034 papers identified, 17 were included in the review, excluding duplicates and those papers unrelated to the topic. One in three samples taken from air close to COVID-19 patients (68/247) contained SARS-CoV-2 RNA. No significant difference was found in the presence of RNA by location (ICU vs. non-ICU) or by distance (<1 meter vs. 1 to 5 meters). Viral RNA was found in samples from other non COVID-19 specific areas, including bathrooms, other clinical areas, staff areas, and public areas. The percentage of samples coming back with positive detection of viral RNA was highest in public areas (34.1% or 14/41). The median concentration of RNA was higher in the air of bathrooms than in clinical areas.

Study Strengths

The methods of the review are well-detailed and follow PRISMA guidelines.


Methods used to collect and analyze air samples are disparate across studies included, and context around the samples collected was not regularly reported (e.g. location, ventilation, distance, clinical context). It is unclear whether the studies included are actually comparable and should be analyzed together as this scoping review has done.

Value added

This study compiles the evidence related to viral RNA presence in air samples in hospital settings.

This review was posted on: 16 October 2020