Efficacy of Facial Mask Use in COVID-19 Transmission Using a Bacterial Model

The prevention of COVID-19, caused by SARS-CoV-2, involves reducing transmission of infectious respiratory droplets and aerosols with different methods, including the use of face masks. There have been a variety of studies published about the effectiveness of face masks — they have been recognised as an inexpensive yet expedient prevention method. In this research we aimed to investigate the microbial contamination of used face masks and to compare the results based on mask usage time to determine the efficiency of facial mask use against COVID-19. Microbiological contamination of 51 used face masks was analysed by the imprinting method on suitable cultivation agars and colony forming units were determined. The majority of microorganisms found in our study were those of normal human skin and respiratory tract microbiota. A greater number of bacterial species was found on the outsides of the facial masks, which furthermore increased with prolonged usage time. We conclude that face mask use is effective in both detaining excreted microorganisms as well as protecting the wearer from microbes in the air, and therefore, should be implemented in the prevention strategies of respiratory diseases. Furthermore, our results show the importance of correct facial mask usage by their contamination with a spectrum of microorganisms.