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A Better Disinfectant for Low-Resourced Hospitals? A Multi-Period Cluster Randomised Trial Comparing Hypochlorous Acid with Sodium Hypochlorite in Nigerian Hospitals: The EWASH Trial

Gon, Giorgia; Dansero, Lucia; Aiken, Alexander M.; Bottomley, Christian; Dancer, Stephanie J.; Graham, Wendy J.; Ike, Olivia C.; Lewis, Michelle; Meakin, Nick; Okafor, Obiora; Uwaezuoke, Nkolika S.; Okwor, Tochi Joy


Giorgia Gon

Lucia Dansero

Alexander M. Aiken

Christian Bottomley

Wendy J. Graham

Olivia C. Ike

Michelle Lewis

Nick Meakin

Obiora Okafor

Nkolika S. Uwaezuoke

Tochi Joy Okwor


Environmental hygiene in hospitals is a major challenge worldwide. Low-resourced hospitals in African countries continue to rely on sodium hypochlorite (NaOCl) as major disinfectant. However, NaOCl has several limitations such as the need for daily dilution, irritation, and corrosion. Hypochlorous acid (HOCl) is an innovative surface disinfectant produced by saline electrolysis with a much higher safety profile. We assessed non-inferiority of HOCl against standard NaOCl for surface disinfection in two hospitals in Abuja, Nigeria using a double-blind multi-period randomised cross-over study. Microbiological cleanliness [Aerobic Colony Counts (ACC)] was measured using dipslides. We aggregated data at the cluster-period level and fitted a linear regression. Microbiological cleanliness was high for both disinfectant (84.8% HOCl; 87.3% NaOCl). No evidence of a significant difference between the two products was found (RD = 2%, 90%CI: −5.1%–+0.4%; p-value = 0.163). We cannot rule out the possibility of HOCl being inferior by up to 5.1 percentage points and hence we did not strictly meet the non-inferiority margin we set ourselves. However, even a maximum difference of 5.1% in favour of sodium hypochlorite would not suggest there is a clinically relevant difference between the two products. We demonstrated that HOCl and NaOCl have a similar efficacy in achieving microbiological cleanliness, with HOCl acting at a lower concentration. With a better safety profile, and potential applicability across many healthcare uses, HOCl provides an attractive and potentially cost-efficient alternative to sodium hypochlorite in low resource settings.

Journal Article Type Article
Acceptance Date Apr 13, 2022
Online Publication Date Apr 26, 2022
Publication Date 2022
Deposit Date May 23, 2022
Publicly Available Date May 23, 2022
Publisher MDPI
Peer Reviewed Peer Reviewed
Volume 10
Issue 5
Article Number 910
Keywords hypochlorous acid; disinfectant; hospital; environmental hygiene; Nigeria
Public URL


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