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BMJ ; 377: o1408, 2022 06 29.
Article in English | MEDLINE | ID: covidwho-1909709

COVID-19 , SARS-CoV-2 , Humans
Microorganisms ; 10(5)2022 Apr 26.
Article in English | MEDLINE | ID: covidwho-1875708


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.

Indoor Air ; 32(1): e12938, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1480133


Self-contamination during doffing of personal protective equipment (PPE) is a concern for healthcare workers (HCW) following SARS-CoV-2-positive patient care. Staff may subconsciously become contaminated through improper glove removal; so, quantifying this exposure is critical for safe working procedures. HCW surface contact sequences on a respiratory ward were modeled using a discrete-time Markov chain for: IV-drip care, blood pressure monitoring, and doctors' rounds. Accretion of viral RNA on gloves during care was modeled using a stochastic recurrence relation. In the simulation, the HCW then doffed PPE and contaminated themselves in a fraction of cases based on increasing caseload. A parametric study was conducted to analyze the effect of: (1a) increasing patient numbers on the ward, (1b) the proportion of COVID-19 cases, (2) the length of a shift, and (3) the probability of touching contaminated PPE. The driving factors for the exposure were surface contamination and the number of surface contacts. The results simulate generally low viral exposures in most of the scenarios considered including on 100% COVID-19 positive wards, although this is where the highest self-inoculated dose is likely to occur with median 0.0305 viruses (95% CI =0-0.6 viruses). Dose correlates highly with surface contamination showing that this can be a determining factor for the exposure. The infection risk resulting from the exposure is challenging to estimate, as it will be influenced by the factors such as virus variant and vaccination rates.

Air Pollution, Indoor , COVID-19 , Fomites , Occupational Exposure , Personal Protective Equipment , Fomites/virology , Gloves, Protective/virology , Hospitals , Humans , Personal Protective Equipment/virology , SARS-CoV-2
Surgery (Oxf) ; 39(11): 752-758, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1466799


Hospitals under pressure from the COVID-19 pandemic have experienced an additional challenge due to clusters of hospital-acquired COVID-19 infection occurring on non-COVID-19 wards. These clusters have involved both staff and patients and compromise staffing, bed management and routine care, especially delivery of elective surgical procedures. They have also contributed towards the overall morbidity and mortality of the pandemic. COVID-19 infection rates are rising again, so it is important to consider implementing additional activities designed to impede transmission of SARS-CoV-2 in acute hospitals. These aim to protect staff, patients and visitors, and conserve safe and continued access for patients needing routine and emergency surgical interventions. Current infection prevention strategies include hand hygiene; patient and staff screening; surveillance; personal protective equipment; cohorting and isolation; and enhanced cleaning. Additional activities include restriction of staff and patient movement; COVID-19 pathways for wards, operating theatres and outpatient services; bathroom management; and ensuring fresh air in the absence of effective mechanical ventilation systems. Seasonal pressures and spread of more contagious and/or vaccine-tolerant variants will continue to disrupt routine and emergency care of non-COVID-19 patients, as well as increase the risk of COVID-19 infection for staff and patients. Supplementary practical and cost-effective actions to limit spread in hospitals are explored in this article.

Sci Total Environ ; 792: 148341, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1275700


Public toilets and bathrooms may act as a contact hub point where community transmission of SARS-CoV-2 occurs between users. The mechanism of spread would arise through three mechanisms: inhalation of faecal and/or urinary aerosol from an individual shedding SARS-CoV-2; airborne transmission of respiratory aerosols between users face-to-face or during short periods after use; or from fomite transmission via frequent touch sites such as door handles, sink taps, lota or toilet roll dispenser. In this respect toilets could present a risk comparable with other high throughput enclosed spaces such as public transport and food retail outlets. They are often compact, inadequately ventilated, heavily used and subject to maintenance and cleaning issues. Factors such as these would compound the risks generated by toilet users incubating or symptomatic with SARS-CoV-2. Furthermore, toilets are important public infrastructure since they are vital for the maintenance of accessible, sustainable and comfortable urban spaces. Given the lack of studies on transmission through use of public toilets, comprehensive risk assessment relies upon the compilation of evidence gathered from parallel studies, including work performed in hospitals and prior work on related viruses. This narrative review examines the evidence suggestive of transmission risk through use of public toilets and concludes that such a risk cannot be lightly disregarded. A range of mitigating actions are suggested for both users of public toilets and those that are responsible for their design, maintenance and management.

Bathroom Equipment , COVID-19 , Aerosols , Humans , SARS-CoV-2 , Toilet Facilities
Indoor Air ; 31(2): 314-323, 2021 03.
Article in English | MEDLINE | ID: covidwho-796060


During the 2020 COVID-19 pandemic, an outbreak occurred following attendance of a symptomatic index case at a weekly rehearsal on 10 March of the Skagit Valley Chorale (SVC). After that rehearsal, 53 members of the SVC among 61 in attendance were confirmed or strongly suspected to have contracted COVID-19 and two died. Transmission by the aerosol route is likely; it appears unlikely that either fomite or ballistic droplet transmission could explain a substantial fraction of the cases. It is vital to identify features of cases such as this to better understand the factors that promote superspreading events. Based on a conditional assumption that transmission during this outbreak was dominated by inhalation of respiratory aerosol generated by one index case, we use the available evidence to infer the emission rate of aerosol infectious quanta. We explore how the risk of infection would vary with several influential factors: ventilation rate, duration of event, and deposition onto surfaces. The results indicate a best-estimate emission rate of 970 ± 390 quanta/h. Infection risk would be reduced by a factor of two by increasing the aerosol loss rate to 5 h-1 and shortening the event duration from 2.5 to 1 h.

COVID-19/epidemiology , COVID-19/transmission , Singing , Ventilation/methods , Fomites/virology , Humans , SARS-CoV-2 , Time Factors , Washington/epidemiology
Emerg Infect Dis ; 26(9): 2064-2068, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-381792


As a result of the coronavirus disease pandemic, commercial hand hygiene products have become scarce and World Health Organization (WHO) alcohol-based hand rub formulations containing ethanol or isopropanol are being produced for hospitals worldwide. Neither WHO formulation meets European Norm 12791, the basis for approval as a surgical hand preparation, nor satisfies European Norm 1500, the basis for approval as a hygienic hand rub. We evaluated the efficacy of modified formulations with alcohol concentrations in mass instead of volume percentage and glycerol concentrations of 0.5% instead of 1.45%. Both modified formulations met standard requirements for a 3-minute surgical hand preparation, the usual duration of surgical hand treatment in most hospitals in Europe. Contrary to the originally proposed WHO hand rub formulations, both modified formulations are appropriate for surgical hand preparation after 3 minutes when alcohol concentrations of 80% wt/wt ethanol or 75% wt/wt isopropanol along with reduced glycerol concentration (0.5%) are used.

Betacoronavirus , Coronavirus Infections/prevention & control , Hand Hygiene/standards , Hand Sanitizers/standards , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , 2-Propanol/analysis , COVID-19 , Ethanol/analysis , Europe , Hand/microbiology , Hand Hygiene/methods , Hand Sanitizers/analysis , Humans , SARS-CoV-2 , World Health Organization