Global Journal of Medical Research, F: Diseases, Volume 23 Issue 2

Relationship between COVID-19 and use of Chlorine Dioxide Gas-Releasing Agents in Elementary Schools Yoshinori Kubo α , Takanori Miura σ , Kaoru Obinata ρ , Ken Hisata Ѡ , Mitsuyoshi Suzuki ¥ , Eisuke Inage § , Naotake Yanagisawa χ , Hiromichi Shoji ν , Norio Ogata Ѳ , Jo Shibata ζ , Takashi Shibata £ & Toshiaki Shimizu € Abstract- Chlorine dioxide has an inactivating effect on various types of viruses in vitro, including severe acute respiratory syndrome coronavirus 2. Therefore, chlorine dioxide gas can be used as a new preventive measure against coronavirus disease 19 (COVID-19). However, no studies have been conducted to investigate the relationship between the incidence of COVID-19 and chlorine dioxide. We retrospectively studied the occurrence of COVID-19 in 164 public elementary schools under the jurisdiction of boards of education located in urban areas in Japan, provided with chlorine dioxide gas-releasing agents or not, from January to March 2022. The odds of developing COVID-19 were lower (odds ratio: 0.934, 95% confidence interval: 0.895–0.975) in schools provided with chlorine dioxide gas-releasing agents than in schools without them. This suggested a relationship between the use of chlorine dioxide-releasing agents and the incidence of COVID-19. Further studies are needed to prove a causal relationship between them. Keywords: chlorine dioxide, COVID-19, infection prevention, elementary school, viral infectivity. I. I ntroduction ince December 2019, coronavirus disease 19 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Shang et al., 2020; Zhou et al., 2020) has been a global public health problem (Chen et al., 2020; Xu et al., 2020). Although pediatric patients with COVID-19 often have a milder course than adults, the COVID-19 infection has had a negative impact on children in terms of lost learning opportunities, malnutrition, poverty, and disruption of health services such as routine childhood immunizations (UNICEF, 2022). In the first and second waves of COVID-19 in Japan, the proportion of cases under 20 years of age was less than 15% (Imamura et al., 2021), and children did not suffer from secondary infections (Ko et al., 2022). However, in the sixth wave of the omicron variant, the proportion of cases under 20 Author α σ ρ Ѡ § χ ν € : Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan. e-mail: y.kubo.hj@juntendo.ac.jp Author α σ ρ Ѡ § χ ζ £ € : Department of Mass Infection Prevention, Juntendo University, Tokyo 113-8421, Japan. Author α σ Ѳ ζ £ : Taiko Pharmaceutical Co., Ltd., Osaka 550-0005, Japan. Author: Medical Technology Innovation Center, Juntendo University, Tokyo 113-8421, Japan. years of age rose to 35% (Aizawa et al., 2022). Standard infection control measures include routine precautions such as hand washing, wearing masks, and environmental cleaning. Thorough implementation of these measures is important for the prevention of infection. However, it has been reported that young children often not wash properly their hands and hand washing is less effective. (Harada, 2004) In addition, in terms of environmental cleaning, it is practically impossible to clean areas where hand contact occurs with high frequency, and standard precautions alone are not sufficient to prevent infection. Despite the prevalence of highly infectious variants in all age groups, parents are hesitant to vaccinate their children (Horiuchi et al., 2021; Yoda & Katsuyama, 2021). Therefore, to reduce the adverse effects of COVID-19 on children and prevent the spread of infection, it is desirable to reduce the incidence of COVID-19 through new preventive measures. SARS-CoV-2 is transmitted among human beings primarily through close contact in confined spaces, droplets of respiratory origin, and contaminated surfaces (Cheng et al., 2020; Lai et al., 2020; Sungnak et al., 2020). SARS-CoV-2 can remain on the surface of the vector for several days (Chin et al., 2020; van Doremalen et al., 2020) and is stable for several hours if aerosolized (van Doremalen et al., 2020). Therefore, environmental factors can have a significant impact on transmission in buildings where people are in close proximity, such as schools (Azuma, Kagi, et al., 2020; Azuma, Yanagi, et al., 2020). Especially in Japan, during the sixth wave of SARS-CoV-2 infection, the proportion of infections in children in schools, nursery schools, and kindergartens increased, while the proportion of infection in the family, the main source of infection, decreased (Aizawa et al., 2022). Therefore, schools are considered an important place for the prevention of COVID-19 in children. Chlorine dioxide (CD) exists as a diffusible gas at room temperature that can be distributed over a wide area (Gates, 1998). The effectiveness of low- concentration CD gas, which poses almost no risk to the human body, was demonstrated in an in vitro S 1 Year 2023 Global Journal of Medical Research Volume XXIII Issue II Version I ( D ) F © 2023 Global Journals