Wearing a face mask during the COVID-19 pandemic could be a more important part of the arsenal against the virus than previously thought.

An article in The New England Journal of Medicine suggests that universal face mask wearing “might help reduce the severity of disease and ensure that a greater proportion of new infections are asymptomatic.”

If that premise is correct, the article suggested, face mask wearing could become a form of inoculation “that would generate immunity and thereby slow the spread of the virus” during the global wait for the development of a vaccine.

The journal cited two recent outbreaks of COVID-19 in U.S. food-processing plants where workers were required to wear masks every day.

“The proportion of asymptomatic infections among the more than 500 people who became infected was 95%, with only 5% in each outbreak experiencing mild-to-moderate symptoms,” the medical journal said.

The article also said “case-fatality rates in countries with mandatory or enforced population-wide masking have remained low, even with resurgences of cases after lockdowns were lifted.”

Dr. Monica Gandhi, one of the authors of the article, who is an infectious disease physician at the University of California, San Francisco, told the British newspaper The Telegraph, “It is true that the proportion of asymptomatic infection being increased by masking might increase the proportion of the population who achieve at least short-term immunity to the virus while we await a vaccine.”

She cautioned, however, that more studies about the efficacy of mask wearing are needed.