Can a Mask Make You Immune to Covid?

Scientists explore an old treatment while we wait for a vaccine

Nurse vaccinates woman against smallpox, diphtheria, and typhoid. (Library of Congress, Public Domain).

In a recent article, published in the New England Journal of Medicine, researchers Monica Ghandi and George Rutherford proposed that wearing a face mask might stimulate an immune response to the Covid-19 virus. The benefits of wearing a face mask are widely acknowledged. The protective barrier reduces the spread of the virus by restricting the number of particles released when an infected person exhales or coughs. A cloth face mask will also filter some — not all — of the virii when an uninfected subject inhales. Rather than admitting a full blast of viral-charged air, the face mask-wearer receives a reduced number of pathogens.

It is this second quality of face masks, the reduction of the number of virii entering the body, that has intrigued Ghandi and Rutherford. In their article they suggest that if an uninfected person receives a small dose of the virus, their body might have enough time to mount an immune response and overcome the invading particles. This would lead to immunity to the disease.

In other words, one of the unacknowledged benefits of wearing a face mask is that it might produce the same immunity that we hope to find in a future, fully-realized vaccine.

The principle that underpins this notion is a very old idea known as “variolation,” a medical practice that dates back to the late medieval period.

Smallpox headlined a list of terrible pre-modern diseases. It ravaged populations across Europe, Asia, and, when the colonists crossed the Atlantic, the Americas. Early physicians tried many remedies, but the most successful — variolation — originated in China. According to William Langer, Chinese physicians would harvest and dry material from the pustules of an infected person. The person receiving treatment would then inhale this viral-laden dust and contract a mild form of smallpox.

It was a bit of a crap shoot — physicians were unable to measure their dosage precisely. Too much of the virus and the patient would die from a full-blown case of smallpox; too little and there would not be an immune response. Nevertheless, when it worked, it worked well: the patient lived and gained immunity against a disease that killed…