Could the mask — already seen by many scientists as the most effective shield against Covid-19 — have yet another benefit? Some researchers now believe that they expose wearers to smaller, less harmful doses of the disease which spark an immune response.

This as yet unproven theory suggests that masks could help inoculate people while we wait for a vaccine. 

Non-medical fabric masks or disposable masks were suggested as precautionary measures to curtail the spread of the novel coronavirus by the World Health Organization. While masks do not offer full protection, masks reduce the amount of virus inhaled by the person wearing it according to a recent paper published in September in the prestigious New England Journal of Medicine. 

Author Monica Gandhi, one of the authors of the paper, is a specialist in infectious. Gandhi told AFP, “We hypothesise that the higher a dose (or inoculum) of virus you get into your body, the more sick you get.”

“We think that masks reduce that dose of virus that you inhale and, thereby, drive up rates of asymptomatic infection,” Gandhi, director of the UCSF-Gladstone Center for AIDS Research said.

She added that asymptomatic infection was linked to a strong immune response from T lymphocytes- a white blood cell-that may act against COVID-19.

“We think masks can act as a sort of ‘bridge’ to a vaccine by giving us some immunity”, Gandhi said and added that researchers are extensively studying and testing the theory.

Bruno Hoen the director at the Institute Pasteur in Paris told AFP, “Of course, it’s still a theory, but there are many arguments in its favour.”

He said we should “take a different look at the use of masks”, which were initially deemed unnecessary by health authorities, against the backdrop of shortages.

The theory echoes “variolation” a technique used before vaccines were developed, the process involves giving a person a mild illness to try an inoculate them against more serious variants of the disease.

The article published in the NEJM states a parallel idea that being exposed to small doses of virus boosts immunity.

While some scientists are cautiously optimistic about the study others like Angela Rasmussen has said she was “pretty skeptical of this being a good idea.”

She added that scientists haven’t yet figured out if lower doses of the virus do mean a milder illness.