Antimicrobial mouthwashes (gargling) and nasal sprays to protect healthcare workers when undertaking aerosol‐generating procedures (AGPs) on patients without suspected or confirmed COVID‐19 infection (Review)

Martin J. Burton* (Corresponding Author), Janet E. Clarkson, Beatriz Goulao, Anne-Marie Glenny, Andrew J. McBain, Anne G.M. Schilder, Katie E. Webster, Helen V Worthington

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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COVID‐19 infection poses a serious risk to patients and – due to its contagious nature – to those healthcare workers (HCWs) treating them. The risks of transmission of infection are greater when a patient is undergoing an aerosol‐generating procedure (AGP). Not all those with COVID‐19 infection are symptomatic, or suspected of harbouring the infection. If a patient who is not known to have or suspected of having COVID‐19 infection is to undergo an AGP, it would nonetheless be sensible to minimise the risk to those HCWs treating them.

If the mouth and nose of an individual undergoing an AGP are irrigated with antimicrobial solutions, this may be a simple and safe method of reducing the risk of any covert infection being passed to HCWs through droplet transmission or direct contact. Alternatively, the use of antimicrobial solutions by the HCW may decrease the chance of them acquiring COVID‐19 infection. However, the use of such antimicrobial solutions may be associated with harms related to the toxicity of the solutions themselves or alterations in the natural microbial flora of the mouth or nose.

To assess the benefits and harms of antimicrobial mouthwashes and nasal sprays administered to HCWs and/or patients when undertaking AGPs on patients without suspected or confirmed COVID‐19 infection.

Search methods
Information Specialists from Cochrane ENT and Cochrane Oral Health searched the Central Register of Controlled Trials (CENTRAL 2020, Issue 6); Ovid MEDLINE; Ovid Embase and additional sources for published and unpublished trials. The date of the search was 1 June 2020.

Selection criteria
This is a question that urgently requires evidence, however at the present time we did not anticipate finding many completed RCTs. We therefore planned to include the following types of studies: randomised controlled trials (RCTs); quasi‐RCTs; non‐randomised controlled trials; prospective cohort studies; retrospective cohort studies; cross‐sectional studies; controlled before‐and‐after studies. We set no minimum duration for the studies.

We sought studies comparing any antimicrobial mouthwash and/or nasal spray (alone or in combination) at any concentration, delivered to the patient or HCW before and/or after an AGP.

Data collection and analysis
We used standard Cochrane methodological procedures. Our primary outcomes were: 1) incidence of symptomatic or test‐positive COVID‐19 infection in HCWs or patients; 2) significant adverse event: anosmia (or disturbance in sense of smell). Our secondary outcomes were: 3) COVID‐19 viral content of aerosol (when present); 4) change in COVID‐19 viral load at site(s) of irrigation; 5) other adverse events: changes in microbiome in oral cavity, nasal cavity, oro‐ or nasopharynx; 6) other adverse events: allergy, irritation/burning of nasal, oral or oropharyngeal mucosa (e.g. erosions, ulcers, bleeding), long‐term staining of mucous membranes or teeth, accidental ingestion. We planned to use GRADE to assess the certainty of the evidence for each outcome.

Main results
We found no completed studies to include in this review.

Authors' conclusions
We identified no studies for inclusion in this review, nor any ongoing studies. The absence of completed studies is not surprising given the relatively recent emergence of COVID‐19 infection. However, we are disappointed that this important clinical question is not being addressed by ongoing studies.
Original languageEnglish
Article numberCD013628
Number of pages24
JournalCochrane Database of Systematic Reviews
Issue number9
Publication statusPublished - 16 Sept 2020

Bibliographical note

We would like to thank the peer reviewers, Professor Jeremy Bagg, Dr Karolin Hijazi, Professor Carl Philpott and Professor Claire Hopkins, fortheirinsightful comments, which helped us to improve these reviews. Thanks also to Professor Peter Tugwell, Senior Editor Cochrane MOSS Network, for acting as sign-oF editor for these projects. We are also grateful to Doug Salzwedel from the Cochrane Hypertension Group for providing search peerreview comments for the draK search strategy. Professor Schilder's time for this project was supported by the National Institute for Health Research, University College London Hospitals Biomedical Research Centre, London, UK. This project was supported by the National Institute for Health Research, via Cochrane Infrastructure, Cochrane Programme Grant
or Cochrane Incentive funding to Cochrane ENT and Cochrane Oral Health. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the Systematic Reviews Programme, NIHR, NHS or the Department of Health.




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