Researchers conclude that homemade masks and some medical masks can withstand simple disinfection without significantly reducing their effectiveness.
A new study has found that disinfecting homemade masks by heating them may not significantly reduce their effectiveness — and that some medical masks can undergo this process and still be effective.
The research, published in the Journal of the International Society for Respiratory Protection, may be valuable for reducing the pressure on stocks of medical masks during the coronavirus disease 19 (COVID-19) pandemic.
According to the World Health Organization (WHO), the virus that causes COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is primarily transmitted by coughing and sneezing.
Droplets of saliva and discharge from the nose can carry the virus. It can be directly passed on if, for example, someone with the infection coughs or sneezes, and another person in close proximity breathes in the resulting droplets.
The virus can also survive on surfaces that the droplets land on. Transmission can occur if a person comes into contact with the droplets on a surface and the virus gains access to the person’s body — if, for example, the person touches their face.
There is also evidence that some people with the infection experience few, if any, symptoms and may still be able to pass on the virus.
As a consequence, the Centers for Disease Control and Prevention (CDC) have recommended wearing cloth face coverings in situations when it is difficult or impossible to maintain a distance of 6 feet between people.
They urge people to make their own face masks and reserve surgical masks and N-95 respirators for healthcare workers. The CDC have produced a guide on how to make a face mask at home.
In light of this advice, the researchers behind the present study set out to investigate ways of disinfecting masks safely — killing any SARS-CoV-2 without reducing the effectiveness of the masks over time.
They studied means of disinfecting homemade masks and those for healthcare workers, as reusing masks may help ease pressure on dwindling stocks.
The study authors cite previous research demonstrating that heating masks to 70oC (