• The two University of California, San Francisco, doctors theorize minimal exposure could produce asymptomatic immunity responses in 80% of the population
  • Presymptomatic and asymptomatic people shed as much virus as those with full-blown COVID-19 cases
  • Nearly 189,500 Americans have died so far from COVID-19

A commentary in the New England Journal of Medicine published Tuesday posits wearing a facial mask may allow the wearer to be exposed to just enough of the coronavirus to provoke an immune response, serving as a crude vaccine.

The commentary by Drs. Monica Gandhi and George W. Rutherford of the University of California, San Francisco, said the exposure could blunt the severity of the disease, ensuring a larger number of infections could remain asymptomatic.

“If this hypothesis is borne out, universal masking could become a form of ‘variolation’ that would generate immunity and thereby slow the spread of the virus in the United States and elsewhere, as we await a vaccine,” the authors wrote.

The United States had logged more than 6.3 million coronavirus infections and nearly 189,500 COVID-19 deaths by late afternoon Tuesday, Johns Hopkins data indicated.

Gandhi and Rutherford noted presymptomatic and asymptomatic people shed just as much virus as patients with full-blown cases. They also note there’s a strong correlation between universal mask-wearing and disease containment, and between the amount of virus received and severity of disease.

Some 40% of coronavirus cases are asymptomatic, but experts say the rate could be as high as 80% if widespread masking is adopted.

“In an outbreak on a closed Argentinian cruise ship, for example, where passengers were provided with surgical masks and staff with N95 masks, the rate of asymptomatic infection was 81% [as compared with 20% in earlier cruise ship outbreaks without universal masking],” they said. “In two recent outbreaks in U.S. food-processing plants, where all workers were issued masks each day and were required to wear them, 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 authors also noted vaccine trials have indicated a lessening in the severity of the virus if it was not completely prevented.

Gandhi and Rutherford called for further studies to test their theory.

Arizona epidemiologist Saskia Popescu told the New York Times the theory “seems like a leap.”

“We don’t have a lot to support it,” Popescu said, adding it could lead to a false sense of complacency, putting people at even higher risk.

There currently are 37 vaccines in clinical trials and at least 91 others in preclinical development. President Trump has said one could be ready within weeks.