At the beginning of the COVID-19 pandemic, I wrote a blog about the importance of being outdoors and how easily the virus spreads indoors, despite mask wearing. I emphasized the best ways to reduce the spread of the virus, in order of effectiveness: 1) ventilation, 2) filtration, and 3) mask wearing.
A significant amount of data now indicates that indoor transmission of the virus far outstrips outdoor transmission. This is likely the result of longer exposure times and decreased turbulence levels (and therefore dispersion) found indoors.[i] A recently published paper in JAMA[ii] has confirmed exactly that.
Ventilation and Filtration Reduce the Concentration of Viral Particles
There is no question that the most effective methods to reduce the concentration of SARS-CoV-2 particles in indoor air include ventilation and filtration. Observational studies along with modeling suggest substantial effectiveness for these strategies used alone, combined, and with other approaches.
For example, in one study conducted in 2020 that included 169 Georgia elementary schools, the incidence of COVID-19 was 39% lower in 87 schools that improved ventilation compared with 37 schools that did not; 35% lower in 39 schools that improved ventilation through dilution alone; and 48% lower in 31 schools that improved ventilation through dilution along with the addition of improved filtration.[iii] A simulation model found that filtration with two high-efficiency particulate air (HEPA) cleaners alone or combined with mask wearing could potentially reduce exposure to infectious particles by an estimated 65% or 90%, respectively.[iv]
An individual can wear a mask in an attempt to prevent the spread of COVID-19, but as these studies found, it is more important to open windows and doors, turn on fans and open vents, and use portable air cleaners. Honestly, I don’t understand why these simple methods were not employed at the onset of the pandemic. Instead, we went crazy with disinfection, often with strong chemicals, only to find out this had little to no effect on stopping the spread of COVID-19.
The Dangers of Disinfectants
In the attempt to prevent and control infection, the use of disinfectants skyrocketed during the COVID-19 pandemic. But there are significant concerns regarding the large-scale use of disinfectants and sanitizers, including worrisome effects on human and animal health and harmful impacts on the environment and ecological balance.[v]
Studies show the excessive use of disinfectants poses a potential threat to living beings and ecosystems,[vi] with a myriad of side effects reported.[vii] For example, using chlorine bleach increases the risk of asthma, chronic obstructive pulmonary disease, infertility, and impaired brain development in children.[viii] Even the seemingly benign act of too-frequent hand washing with soap and alcohol-based sanitizers can cause painfully dry, cracked skin and potential skin infections. More alarming is that alcohol-based sanitizers can cause alcohol poisoning, especially in infants or young children.[ix]
An Israeli worker in a hazmat suit sprays disinfectant in the cabin of an Israir Airlines Airbus A320 airplane at Ben Gurion International Airport on June 14, 2020. Gil Cohen-Magen/AFP via Getty Images
A Reality Check from the CDC
In April of 2021, the CDC finally admitted that COVID-19 infections very rarely spread to people from surfaces.[x] However, because of fear instilled by the pandemic, many people have not relinquished their need to constantly disinfect and sanitize themselves and everything they come into contact with. Adding to the disinfection obsession is that many private and public businesses and venues employ drastic fumigation measures in an attempt to reassure the wary public.
It’s important to realize that the fumigation of outdoor spaces, such as streets, sidewalks, unpaved walkways, and marketplaces is not a useful tool for eradicating the COVID-19 virus or any other pathogen. Any type of disinfectant is immediately inactivated by dirt and debris.[xi]
Here’s a disturbing statistic: In China, 2000–5000 tons of disinfectants have been dispensed in Wuhan alone since the beginning of the pandemic.[xii]
Overuse of Disinfectants is Leading to Pathogenic Resistance through Hormenis
The overuse of disinfectants is creating a serious problem. Collated evidence from multiple studies shows that the chemicals used for disinfectant products can induce hormesis in plants, animal cells, and microorganisms. This is true when applied singly or in mixtures, suggesting potential ecological risks at sub-threshold doses that are normally considered safe.
Among other negative effects, sub-threshold doses of disinfectant chemicals can enhance the proliferation and pathogenicity of pathogenic microbes, enhancing the development and spread of drug resistance.
The massive application of disinfectants for containing COVID-19 is a double-edged sword, in that it may inhibit/prevent the virus but also imposes potentially significant but non-apparent costs or risks by affecting other non-target organisms in a dose-dependent manner, and by promoting traits of drug resistance.[xiii]
Weighing the Risk-to-Benefit Ratio
We need to do a better job when it comes to weighing the risk-to-benefit ratio of practices such as widespread disinfection. And we need to evaluate these practices carefully, considering the immediate side effects and the long-term implications.
I always advocate for a less invasive, more natural approach for supporting health. In terms of disinfection, I recommend using essential oils instead of chemicals. Plant extracts and essential oils provide a full-spectrum and safer approach to mediating the spread of viruses, without any of the detrimental personal or environmental effects of chemicals. For more on this, see my blog from December 17, 2021, entitled “Essential Oils with Anti-Viral Properties” at https://www.donnieyance.com/essential-oils-with-anti-viral-properties/.
[i] Bhagat, R., Davies Wykes, M., Dalziel, S., & Linden, P. (2020). Effects of ventilation on the indoor spread of COVID-19. Journal of Fluid Mechanics, 903, F1. doi:10.1017/jfm.2020.720
[ii] Dowell D, Lindsley WG, Brooks JT. Reducing SARS-CoV-2 in Shared Indoor Air. JAMA. Published online June 07, 2022. doi:10.1001/jama.2022.9970
[iii] Gettings J, Czarnik M, Morris E, et al. Mask use and ventilation improvements to reduce COVID-19 incidence in elementary schools—Georgia, November 16–December 11, 2020. MMWR Morb Mortal Wkly Rep. 2021;70(21):779-784. doi:10.15585/mmwr.mm7021e1PubMedGoogle ScholarCrossref
[iv] Lindsley WG, Derk RC, Coyle JP, et al. Efficacy of portable air cleaners and masking for reducing indoor exposure to simulated exhaled SARS-CoV-2 aerosols—United States, 2021. MMWR Morb Mortal Wkly Rep. 2021;70(27):972-976. doi:10.15585/mmwr.mm7027e1
[v] Dhama, K., Patel, S. K., Kumar, R., Masand, R., Rana, J., Yatoo, M. I., Tiwari, R., Sharun, K., Mohapatra, R. K., Natesan, S., Dhawan, M., Ahmad, T., Emran, T. B., Malik, Y. S., & Harapan, H. (2021). The role of disinfectants and sanitizers during COVID-19 pandemic: advantages and deleterious effects on humans and the environment. Environmental science and pollution research international, 28(26), 34211–34228. https://doi.org/10.1007/s11356-021-14429-w
[vi] Chen Z, Guo J, Jiang Y, Shao Y. High concentration and high dose of disinfectants and antibiotics used during the COVID-19 pandemic threaten human health. Environ Sci Eur. 2021;33(1):11. doi: 10.1186/s12302-021-00456-4.
[vii] Yari S, Moshammer H, Asadi AF, Mosavi Jarrahi A. Side effects of using disinfectants to fight covid-19. Asian Pacific Journal of Environment and Cancer. 2020;3(1):9013. doi: 10.31557/apjec.2020.3.1.9-13.
[viii] Fair D (2020) Issues of the environment: chemical impacts In fighting the spread of COVID-19. https://www.wemu.org/post/issues-environment-chemical-impacts-fighting-spread-covid-19. Accessed 24 June 2020
[ix] Santos, C., Kieszak, S., Wang, A., Law, R., Schier, J., Wolkin, A.J.M.M., report, m.w., 2017. Reported adverse health effects in children from ingestion of alcohol-based hand sanitizers—United States, 2011–2014. 66, 223.
[xi] Ghafoor D, Khan Z, Khan A, Ualiyeva D, Zaman N. Excessive use of disinfectants against COVID-19 posing a potential threat to living beings. Curr Res Toxicol. 2021;2:159-168. doi: 10.1016/j.crtox.2021.02.008. Epub 2021 Mar 4. PMID: 33688633; PMCID: PMC7931675.
[xii] Zhang H., Tang W., Chen Y., Yin W. Disinfection threatens aquatic ecosystems. Science. 2020;368:146–147. doi: 10.1126/science.abb8905
[xiii] Agathokleous, E., Barceló, D., Iavicoli, I., Tsatsakis, A., & Calabrese, E. J. (2022). Disinfectant-induced hormesis: An unknown environmental threat of the application of disinfectants to prevent SARS-CoV-2 infection during the COVID-19 pandemic?. Environmental pollution (Barking, Essex : 1987), 292(Pt B), 118429. https://doi.org/10.1016/j.envpol.2021.118429