Decontamination and reuse of surgical masks and respirators during COVID-19 pandemic

Côrtes, Marina Farrel; Espinoza, Evelyn Patricia Sanchez; Noguera, Saidy Liceth Vásconez; Silva, Aline Alves; de Medeiros, Marion Elke Sielfeld Araya; Boas, Lucy Santos Villas; Ferreira, Noely Evangelista; Tozetto-Mendoza, Tania Regina; Morais, Fernando Gonçalves; de Queiroz, Rayana Santiago; de Proenca, Adriana Coracini Tonacio; Guimaraes, Thais; Guedes, Ana Rubia; Letaif, Leila Suemi Harima; Montal, Amanda Cardoso; Mendes-Correa, Maria Cassia; John, Vanderley M.; Levin, Anna S.; Costa, Silvia Figueiredo

OBJECTIVES: Coronavirus disease 2019 pandemic increased demand on personal protective equipment(PPE) causing shortages. We evaluated surgical masks and respirators reuse by analyzing their performance and safety before and after decontamination methods: oven, thermal drying, autoclave, and hydrogen peroxide plasma vapor. METHODS: 45 surgical masks and 69 respirators were decontaminated. We evaluated the visual integrity, air permeability, burst resistance, pressure differential, and particulate filtration efficiency of new and decontaminated masks. We also analyzed 14 used respirators, after work shifts, before and after decontamination by RT-PCR and viral culturing. Finally, reprocessed masks were evaluated by users as to functionality and comfort. RESULTS: The most simple and useful method was dry heat in the oven(75 °C for 45 minutes). Physical and filtration assays indicated that all methods were safe after 1 cycle. Oven maintained the characteristics of surgical masks and respirators for at least five reprocessing cycles. We detected viral RNA by RT-PCR in two of 14 used masks. Four masks submitted to viral culture were PCR-negative and culture-negative. Reprocessed respirators used in work shifts were positively evaluated by users even after three decontamination cycles. CONCLUSION: Dry heat is a safe decontamination method of surgical masks and respirators for at least five cycles and is feasible in the hospital.