Universal Mask-Wearing Could Increase Population-Wide COVID-19 Immunity, Say Researchers

In a commentary published in the New England Journal of Medicine, academics have proposed that universal face mask wearing could be reducing the severity of coronavirus and increasing the number of new asymptomatic infections.

Earlier research has suggested that the “infectious dose” or the amount of virus a person is exposed to during the start of infection determines the severity of the illness. In August, a large study published in the Lancet showed that “viral load at diagnosis” was an “independent predictor of mortality” in hospital patients. As a result, wearing a mask could lower the infectious dose that the wearer is exposed to and reduce the impact of the disease, as the mask filters out some of the virus-containing droplets. Based on this theory, the researchers have suggested that population-wide mask wearing could ensure a higher proportion of asymptomatic COVID-19 patients.

Additionally, recent research has revealed that even mild or asymptomatic coronavirus infection can induce strong immune responses. This means that if mask wearing reduces the severity of the coronavirus then it is also likely to increase population-wide immunity, as a low viral load can be sufficient to generate an immune response, which is what a vaccine would also do, according to the Sunday Telegraph report.

“This idea of 'variolation' - a term originally derived from the smallpox pre-vaccine era - is quite feasible and may add to the protective physical effects of universal masking - by low level stimulation of the wearer's immune system as it is exposed to low levels of airborne SARS-CoV-2, which can induce an immune response but without any overt infection and disease,” Dr. Monica Gandhi, an infectious disease physician at the University of California, San Francisco, and one of the paper’s authors, told the Sunday Telegraph. “This is after all the response to a typical vaccine - where the recipient's immune systems are stimulated, subclinically, to produce protective immune responses to combat the infection if exposed at a future date.”