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Year : 2020  |  Volume : 13  |  Issue : 5  |  Page : 427-430  

To spray and pray? The “disinfectant spray” conundrum

1 Technical Advisor, Delta Zulu Consultancy, Pune, India
2 Reconstructive Surgeon, Command Hospital, Bangalore, Karnataka, India
3 Consultant (Joint Replacement), Medanta Hospital, Lucknow, Uttar Pradesh, India
4 Consultant (Acute Medicine and Toxicology), Royal Infirmary of Edinburgh, Scotland, United Kingdom
5 Consultant (Nephrology), Command Hospital, Kolkata, West Bengal, India

Date of Submission25-May-2020
Date of Decision22-Jun-2020
Date of Acceptance03-Jul-2020
Date of Web Publication7-Sep-2020

Correspondence Address:
Mudera P Cariappa
Delta Zulu Consultancy, Aura Solis, Wanowrie, Pune - 411 040, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mjdrdypu.mjdrdypu_281_20

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To contain the spread of the coronavirus, governments have instituted various stringent preventive measures including spraying disinfectants onto open spaces and people too, to reduce the spread of the virus. There is panic driving such responses especially in rural areas, where internally displaced workforces are now returning to their native villages. We seek to analyze the potential impact of such practices as a starting point for further scientific debate. We believe that findings of past studies on disinfection practices are not applicable to the spraying of open spaces or people as the conditions are totally different. We need to balance benefits with the potential for adverse risks of any public disinfection activities. As with other chemicals, spraying disinfectants into the environment is also likely to cause harm in some instances. While public authorities would wish to be seen to be doing something to reduce transmission and allay anxiety in the public, spraying disinfectant over public spaces and onto people could backfire substantially, if real or perceived adverse effects appear. Unanticipated consequences can result if consideration is not given to the Principle of Harm, which determines when Public health interventions are ethically justifiable and there is no attempt to minimize harm in the face of uncertainty. We recommend a systems approach to reporting of unintended harms from such interventions through a community based participatory process and further evaluation before implementation of such measures.

Keywords: Coronavirus disinfection, COVID 19 disinfection, health risks of disinfection, spraying for disinfection

How to cite this article:
Cariappa MP, Bavdekar RD, Kumar N, Veiraiah A, Nair RK. To spray and pray? The “disinfectant spray” conundrum. Med J DY Patil Vidyapeeth 2020;13:427-30

How to cite this URL:
Cariappa MP, Bavdekar RD, Kumar N, Veiraiah A, Nair RK. To spray and pray? The “disinfectant spray” conundrum. Med J DY Patil Vidyapeeth [serial online] 2020 [cited 2021 Nov 28];13:427-30. Available from: https://www.mjdrdypv.org/text.asp?2020/13/5/427/294359

  Introduction Top

The coronavirus pandemic (COVID 19), caused by the severe acute respiratory syndrome (SARS)-CoV-2 virus, has resulted in a major global lockdown, overwhelming many local health resources worldwide.[1] To contain the spread of the virus, governments have instituted various stringent preventive measures. In addition to physical (social) distancing and isolation, news reports from around the world in March–April 2020 indicated that local authorities were spraying disinfectants onto open spaces and people too, to reduce the spread of the virus. Despite such widespread use, a search on PUBMED and Google (using terms such as “Risks of Disinfectant Spray,” “Health effects of Disinfection,” and “Harmful Effects of Disinfection”) did not return any scientific articles on the risks of using disinfectants in such settings. We, therefore, sought to analyze the potential impact of such practices as a starting point for further scientific debate on this matter.

  Public Disinfection Top

Early news reports in January 2020 from China showed trucks spraying unknown disinfectant(s) into Hubei's public spaces.[2] Snow cannons have been used for street spraying in Italy, In Indonesia, drones were used to spray benzalkonium,[3] and in India, tunnel-like systems had been created for people to be sprayed as they walked through them.[4] Every day, in the first few weeks of the pandemic, e-newspapers were replete with information on some new “low cost,” “innovation” (“jugaad”), about some modality involving spraying chemicals in a mist of aerosol form on unsuspecting people. Naught is known about the nature of the chemicals used, and their composition and concentration largely remain out of the public domain in most countries.

  Will Disinfection Sprays Work? Top

Based on anecdotal media reports online, there has been widespread spraying of various chemicals using different modalities worldwide, on environmental surfaces including vehicles and even on fully clothed people, with the coronavirus making its presence felt globally. The recent exodus of internally displaced persons witnessed in India with the rural origin workforce returning back to their roots has led to a flurry of knee jerk reactions, with disinfection sprays being just one of the measures unleashed by a panicked people. Will these work? Are these just an “eyewash?” Are there any harms associated with indiscriminate usage of such sprays?

Disinfection is the removal of pathogens without acting on endospores.[5] Our current knowledge indicates that the SARS-CoV-2 virus remains active in an aerosol form for about 3 h and on most surfaces for about 72 h.[6] This is assumed in the current media frenzy to be the absolute truth, not realizing that these are all interim results from ongoing research. It takes years of rigorous scientific research to conclusively describe these kinds of microorganism characteristics.

Fogging with hydrogen peroxide and chlorine oxide has been shown to be effective in decontaminating surfaces containing norovirus under laboratory test conditions.[7] Fogging with quaternary ammonium compounds[8] and other disinfectants[9] has also been shown to be effective against various pathogenic bacteria (virus load not measured) within hospital spaces under test conditions. These studies ensured the uniform spread of a high concentration of the disinfectant in the ambient atmosphere, kept the rooms sealed for 25 min or more, and took measures to prevent contact of sensitive surfaces with the fog. We believe that the findings of these studies are not applicable to the spraying/fogging of open spaces as the conditions are totally different. Our cause for concern about the effectiveness of disinfectants fogged and sprayed in open spaces is summarized in [Box 1].

Fumigation is another term which is being liberally used by the lay population. However, this is best reserved for specialized areas within hospitals such as operation theaters and should not be confused with other disinfection procedures that can be applied to general settings in the community.

  Balancing Benefits and Adverse Effects Top

Chlorine is in ubiquitous usage since the past 120 years as a chemical disinfectant, serving as the principal agent for disinfection of potable water supplies. The microbicidal attributes of chlorine along with the formation of disinfectant by-products of public health concern during the chlorination process necessitate an understanding of the requirement to balance between microbial and chemical risks. However, for water disinfection, chlorine is at levels of 0.2–0.5 ppm usually, while for surface disinfection as is being envisaged currently, it should be up to 5000 ppm.[11] Those who have frequented swimming pools are conscious of the ocular irritation caused by chlorine at concentrations of more than 2 ppm, and here, we are recommending concentrations up to 5000 ppm, without apparent concern for human safety and comfort.

As with other chemicals, spraying disinfectants into the environment is also likely to cause harm in some if not most instances, apart from the environmental persistence of breakdown by-products. There may be damage to clothes and other surfaces that may occur with indiscriminate area sprays. Individuals may develop skin reactions or secondary effects of irritation of their exposed mucosal surfaces including eyes and respiratory tract. Nurses who regularly work with disinfectants have been shown to have increased risk of chronic obstructive pulmonary disease.[12] Higher concentrations of bleach have been reported to cause significant bronchospasm in more than half of homemakers who used it and needed hospital treatment.[13] It is possible that aerosolized hypochlorite or other disinfectants may reach the alveoli and themselves cause interstitial lung disease and even result in cardiopulmonary injury in susceptible individuals.[14] Spraying onto the public, especially if the recipients are a disadvantaged section of the society, such as migrants or refugees, could even be considered a violation of human rights and negate the efforts of a government to contain the pandemic. The questions, which need to be answered by those who must spray “disinfectants” in public spaces, to show their zeal and enthusiasm, are in [Box 2].

We do not know what are the chemicals and what are the concentrations being used in these “disinfection tunnels” or “disinfection space sprays.” It can be hoped that those who had been deploying these at least had an idea of the required concentrations and were not wholly ad hoc in their approach. Furthermore, it must be kept in focus that disinfectants may be damaging to some fabrics and surfaces (e.g., rubbers and plastics). Safety over normal fabrics (cotton/synthetic/blends) worn by man has also not been effectively established for higher concentrations.

  Discussion Top

While public authorities would understandably wish to be seen to be doing something to reduce transmission and to allay anxiety in the public, spraying disinfectant over public spaces and onto people could backfire substantially, if real or perceived adverse effects appear in the short term or in the long term, for example, a possible association between fluoridation of water and IQ in children.[15] If in the short term, adverse effects are observed, these might reduce public engagement and lead to a loss of faith in governance and capabilities to deal with the crisis.

Recent Government of India[16] and the WHO[17] directives have cautioned against the practice of public spraying for disinfection. However, in far-flung locales across the world and especially in developing countries, the practice may be difficult to be done away with, as the easy availability of chemicals, spraying equipment coupled with fear of the coronavirus, and a lack of understanding of the risks may allow people and their environment to be subjected to chemical sprays. In all this, the internally displaced populations are most at risk for being subjected to the indignity of being chemically “disinfected.” Thus, to pray to be spared, from the coronavirus and the “chemical spray,” may be the only choice for these disadvantaged people.

We urge public agencies considering public spraying of disinfectants now and in the future, to undertake extensive professional consultations a priori, including community participation, and then publicize and reassure the public about details of their plan, with the evidence for effectiveness and safety of the disinfectant when released as an aerosol into the environment or onto people. There should also be a robust mechanism to monitor exposed people and the environment too, for short- and long-term adverse effects.

Public health interventions (PHIs) are usually well meaning and intend to protect the health of communities and populations. However, unanticipated consequences can result if consideration is not given to the principle of harm, which determines when PHIs are ethically justifiable, and there is no attempt to minimize harm in the face of uncertainty (the precautionary principle). We call upon the society at large and professional bodies in specific, to ensure better evaluation of available interventions and recommend a system approach to reporting of unintended harms from such interventions through a community-based participatory process.[18]

  Recommendations Top

In the present COVID19 pandemic times, the clamor for infection control by the public and local authorities alike may lead to overlooking a vital element of any health intervention, i.e., Primum non nocere. First, do no harm, is the diktat we recommend for authorities considering any public disinfection measures, whether in light of the ongoing pandemic or in any such future public health emergencies. We would strongly dissuade against public disinfection measures such as “tunnels” or whole-body sprays.

We recommend that “medical grade” disinfection is carried out only in controlled settings within an institutional health-care setting. For other public and domestic settings, we recommend selective application of disinfection concepts such as wet mopping and frequent disinfectant surface wipe down of high contact surfaces, combined with personal hygiene measures such as handwashing and usage of masks. Recent directives have been issued on this, which are practical and implementable.[16]

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Wang C, Horby PW, Hayden FG, Gao GF. A novel coronavirus outbreak of global health concern. Lancet 2020;395:470-3.  Back to cited text no. 1
Zhong R, Mozur P. To Tame Coronavirus, Mao-Style Social Control Blankets China. The New York Times; 15 February, 2020. Available from: https://www.nytimes.com/2020/02/15/business/china-coronavirus-lockdown.html. [Last accessed on 2020 Apr 30].   Back to cited text no. 2
Wardoyo P, Geddie J. Mass Disinfections to Combat Coronavirus Pose Another Health Hazard. World News; 31 March, 2020. Available from: https://www.reuters.com/article/us-health-coronavirus-disinfection/mass-disinfections-to-combat-coronavirus-pose-another-health-hazard-idUSKBN21I1PB. [Last accessed on 2020 Apr 30]  Back to cited text no. 3
Siddiqui H. Coronavirus: DRDO Creates Full Body Disinfection Chamber and Full Face Mask. Available from: https://www.financialexpress.com/defence/coronavirus-drdo-creates-full-body-disinfection-chamber-and-full-face-mask/1919498/. [Last accessed on 2020 Apr 30].  Back to cited text no. 4
Yoo JH. Review of disinfection and sterilization Back to the basics. Infect Chemother 2018;50:101-9.  Back to cited text no. 5
van Doremalen N, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN, et al. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N Engl J Med 2020;382:1564-7.  Back to cited text no. 6
Montazeri N, Manuel C, Moorman E, Khatiwada JR, Williams LL, Jaykus LA. Virucidal activity of fogged chlorine dioxide- and hydrogen peroxide-based disinfectants against human norovirus and its surrogate, feline calicivirus, on hard-to-reach surfaces. Front Microbiol 2017;8:1031.  Back to cited text no. 7
Nakata S, Ikeda T, Nakatani H, Sakamoto M, Higashidutsumi M, Honda T, et al. Evaluation of an automatic fogging disinfection unit. Environ Health Prev Med 2001;6:160-4.  Back to cited text no. 8
Friedman H, Volin E, Laumann D. Terminal disinfection in hospitals with quaternary ammonium compounds by use of a spray-fog technique. Appl Microbiol 1968;16:223-7.  Back to cited text no. 9
Clarkson RM, Moule AJ, Podlich HM. The shelf-life of sodium hypochlorite irrigating solutions. Aust Dent J 2001;46:269-76.  Back to cited text no. 10
World Health Organization. Environmental Health Criteria 216: Disinfectants and Disinfectant By-Products. World Health Organization; 2000. p. 1-25.  Back to cited text no. 11
Dumas O, Varraso R, Boggs KM, Quinot C, Zock JP, Henneberger PK, et al. Association of occupational exposure to disinfectants with incidence of chronic obstructive pulmonary disease among us female nurses. JAMA Netw Open 2019;2:e1913563.  Back to cited text no. 12
Gorguner M, Aslan S, Inandi T, Cakir Z. Reactive airways dysfunction syndrome in housewives due to a bleach-hydrochloric acid mixture. Inhal Toxicol 2004;16:87-91.  Back to cited text no. 13
Carlisle M, Lam A, Svendsen ER, Aggarwal S, Matalon S. Chlorine-induced cardiopulmonary injury. Ann N Y Acad Sci 2016;1374:159-67.  Back to cited text no. 14
Till C, Green R, Flora D, Hornung R, Martinez-Mier EA, Blazer M, et al. Fluoride exposure from infant formula and child IQ in a Canadian birth cohort. Environ Int 2020;134:105315.  Back to cited text no. 15
Govt of India. COVID-19: Guidelines on Disinfection of Common Public Places Including Offices. Available from: https://www.mohfw.gov.in/pdf/Guidelinesondisinfectionofcommon publicplacesincludingoffices.pdf 20. [Last accessed on 2020 Apr 14].  Back to cited text no. 16
World Health Organization. Cleaning and Disinfection of Environmental Surfaces in the Context of COVID-19: Interim guidance. World Health Organization; 2020.  Back to cited text no. 17
Allen-Scott LK, Hatfield JM, McIntyre L. A scoping review of unintended harm associated with public health interventions: Towards a typology and an understanding of underlying factors. Int J Public Health 2014;59:3-14.  Back to cited text no. 18


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