Health security

Severity of coronavirus infection may be determined by face mask use, study suggests

Face masks may limit the severity of coronavirus cases, University of California San Francisco researchers said in a paper published in the Journal of General Internal Medicine.

Although face coverings are more effective in preventing droplets from being expelled into the air than they are in preventing droplets from being breathed in, masks still may be able to mitigate how severe an illness an individual gets if infected by COVID-19, researchers explained in the release.

“It’s likely that face masks, by blocking even some of the virus-carrying droplets you inhale, can reduce your risk of falling seriously ill from COVID-19," Monica Gandhi, MD, an infectious disease specialist at UC San Francisco, said in a university press release. “The more virus you get into your body, the [sicker] you are likely to get."

Based on the researchers’ epidemiological observations, Gandhi and her colleagues suggest in the paper that masks can lead to milder or asymptomatic infections by reducing the amount of virus people breathe in.

"Masks, depending on [the] type, filter out the majority of viral particles, but not all," the researchers stated in the published report.

The notion of viral dose or viral inoculum was incorporated with early smallpox vaccines in the 16th century in China where small amounts of the virus were injected into a healthy person to create a mild illness followed by immunity. It was also involved with the influenza A virus, where healthy volunteers who received a larger dose of the influenza A virus had symptoms that were more severe, the release said.