Disclaimer: The aim of these rapid reviews is to retrieve, appraise, summarize and update the available evidence on COVID-related health technology. The reviews have not been externally peer- reviewed; they should not replace individual clinical judgement and the sources cited should be checked. The views expressed represent the views of the authors and not necessarily those of their host institutions. The views are not a substitute for professional medical advice.

Copyright Claims: This review is an intellectual property of the authors and of the Institute of Clinical Epidemiology, National Institutes of Health-UP Manila and Asia-Pacific Center for Evidence Based Healthcare Inc.

BACKGROUND

Coronavirus disease (COVID-19) is an infectious disease caused by the novel human coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Philippines reported its first case of COVID-19 on 30 January 2020.1

Human coronaviruses similar to SARS-CoV-2, such as SARS coronavirus, Middle East Respiratory Syndrome (MERS) coronavirus, or endemic human coronaviruses (HCoV) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days. Coronaviruses can be efficiently inactivated within a minute through surface disinfection procedures using 62-71% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite.2

Sanitation tents, also called disinfection tents, have been installed in entrances of city halls, health offices, checkpoints, and other establishments in various areas of the Philippines as a measure to decontaminate individuals and prevent COVID-19 transmission. These tents are designed to “sanitize” persons by spraying or misting disinfectants all over the body. Some tents also provide handwashes and foot baths.3–5 The commonly used disinfectants in the sanitation tents are diluted household bleach, alcohol, and povidone iodine.

This systematic review summarizes the available evidence on the efficacy and safety of sanitation tents in COVID-19 decontamination.

METHODS

See General Methods Section.

Articles were selected based on the following inclusion criteria:

•Population: general population, healthcare workers providing care for COVID-19 patients

•Intervention: sanitation tents

•Comparator: placebo, any active control, no intervention

•Outcomes: COVID-19 transmission

•Study designs: randomized controlled trials (RCTs), non-randomized studies, observational studies (e.g. cohort, case-control, cross-sectional, case report, case series)

RESULTS

There are no completed or ongoing studies on the use of sanitation tents for the prevention of COVID-19 transmission.

There are no guidelines that recommend the use of sanitation tents for prevention of COVID-19 transmission.

DISCUSSION

This review found no available evidence to support the use of sanitation tents for the prevention of the transmission of COVID-19. Review of literature on the commonly used disinfectants in sanitation tents revealed the possible adverse effects that may occur when these chemicals are sprayed or misted on individuals.

Bleach is a disinfectant frequently used for surfaces and laundry of clothes since it can kill most viruses, bacteria, molds, and algae. Common household bleaches are chlorine- based and contain 3-8% sodium hypochlorite.6 Diluted household bleach disinfects within 10-60 minutes of contact time.7 However, bleach decomposes when exposed to heat and sunlight, leading to loss of antimicrobial properties.7,8 It also decomposes with time, and diluted mixtures should be discarded 24 hours after preparation.7 There are several

documented adverse effects of bleach exposure among humans. Bleach is an irritant to mucous membranes. It can cause eye redness, irritation, tearing, and blurring of vision; mouth and throat irritation, skin irritation; and bronchospasm when inadvertently inhaled.6,9

Alcohols can be used as an antiseptic and as a disinfectant. It may contain ethanol, isopropanol or n-propanol, or a combination of two of these products. Solutions containing 60-80% alcohol are most effective, showing antimicrobial activity against bacteria and viruses. Alcohols are rapidly germicidal when applied to the skin, but have no appreciable persistent (residual) activity.10 Alcohol is flammable; hence, the World Health Organization (WHO) recommends to limit its use as a surface disinfectant to small surface areas and only in well-ventilated spaces.7 Alcohol can cause irritation of the eyes and mucous membranes.11 Alcohol toxicity usually occurs after ingestion, but toxicity after inhalation and dermal absorption have been reported.12–15 Symptoms and signs of isopropyl alcohol intoxication include headache, dizziness, incoordination, hypoglycemia, abdominal pain, nausea, vomiting, and hematemesis.12,16

Povidone iodine is an antiseptic that has antimicrobial activity against various viruses, bacteria, and protozoa. In vitro studies demonstrate that povidone iodine has viricidal activity against coronaviruses related to SARS-CoV-2.17 Povidone iodine may cause skin irritation after prolonged contact.18 There are reports of acute kidney injury after systemic absorption of povidone iodine through damaged burned skin, ingestion, or internal administration.19 Chemical pneumonitis was reported following aspiration of povidone iodine.20,21

Repeated exposure to disinfectants has also been associated with the development of chronic obstructive pulmonary disease (COPD) and asthma. A 2019 cohort study among nurses showed that high-level exposure to disinfectants such as bleach, hydrogen peroxide, alcohol, and glutaraldehyde was significantly associated with COPD. The adjusted hazard ratio for COPD for those with weekly use of any disinfectant was 1.35, 95% CI 1.14-1.59.22 Another study reported a significant association between use of household disinfectants with development of asthma among young adults, with an odds ratio of 2.79 (95% CI 1.14-6.83) among those with high use of disinfectants.23

A 2011 systematic review that evaluated physical interventions to prevent the spread of respiratory viruses reported hand hygiene was the intervention supported by the highest quality of evidence. Use of surgical masks or N95 respirators were also consistently found to be effective. The evidence supporting the addition of viricidal substances or antiseptics to regular hand hygiene (i.e. using soap and water) to decrease transmission of respiratory viruses was reported to be uncertain. This was based on data from 3 randomized controlled trials and 3 prospective cohort studies on antiseptic use, and 3 randomized controlled trials and 1 prospective cohort study on use of viricidal tissues.

Results of these studies were conflicting; meta-analysis was not done for this intervention.24

The WHO explicitly recommends against spraying alcohol or chlorine all over a person’s body due to adverse health effects and the lack of inhibitory activity against viruses that have already entered the body.25

The Centers for Disease Control and Prevention (CDC) note that most environmental protection agency-registered household disinfectants are effective against COVID-19. However, these products are approved for use only on surfaces and not on humans.26

The Department of Health (DOH) guidelines recommend the avoidance of spraying or misting for COVID-19 due to lack of evidence of its efficacy. The DOH also stated that spraying may cause additional health and safety concerns such as dispersing pathogens further, skin irritation and inhalation of chemicals, and environmental pollution. At present, guidelines from the DOH allow the use of the existing disinfection tents only for spraying or misting individuals in full personal protective equipment (PPE), characterized as having no external skin exposure, before doffing their full PPEs.27,28

CONCLUSION

At present, there are no studies that demonstrate the effectiveness and safety of sanitation tents in the prevention of COVID-19 transmission.

Declaration of Conflict of Interest

No conflict of interest.

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