RESUMEN
BACKGROUND: Aluminium reduces severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) survival in experimental settings. It is unknown whether adding an aluminium gauze to a mask reduces the SARS-CoV-2 RNA load in the mask and whether SARS-CoV-2 is detectable in the breath that permeates through such a mask in clinical settings. METHODS: Patients admitted to Kishiwada City Hospital, Osaka, Japan, between July 2021 and September 2021 were enrolled in the study. Non-woven masks comprising filters with 99% viral filtration efficacy and aluminium and cotton gauzes attached to plastic collection cases were developed. All participants wore the experimental mask models for three hours. RESULTS: Twenty-nine patients who wore the final model masks were analysed in this study. The Ct values of the nucleocapsid gene and envelope gene of SARS-CoV-2 were significantly higher in the aluminium gauze than in the cotton gauze. SARS-CoV-2 RNA was detected in the masks of 8 out of 12 vaccinated patients (66.7%). Although breath condensates were collected behind both aluminium and cotton gauzes, SARS-CoV-2 RNA was not detected in these condensates. CONCLUSIONS: Our study indicated that non-woven masks with an aluminium gauze may obstruct SARS-CoV-2 transmission in clinical settings better than non-woven masks with cotton gauzes.
RESUMEN
Bioshell calcium oxide (BiSCaO) is derived from scallop shells and after heat treatment exhibits broad microbicidal activity. BiSCaO Water is a disinfectant prepared by collecting the aqueous layer after adding BiSCaO powder to water, is colorless and transparent, and has a pH of 12.8. We compared the utility of commercially available BiSCaO Water, ethanol, sodium hypochlorite, hypochlorous acid and hydrogen peroxide solutions as sterilization agents to enable the reuse of surgical and N95 face masks. The microbicidal efficacy of each disinfectant was evaluated using pieces of surgical and N95 face masks contaminated with normal bacterial flora. The results suggest that BiSCaO Water has excellent disinfection activity toward contaminated polypropylene masks and has minimal adverse effect on the structure of non-woven masks.
