(p. D8) As the world awaits the arrival of a safe and effective coronavirus vaccine, a team of researchers has come forward with a provocative new theory: that masks might help to crudely immunize some people against the virus.
The unproven idea, described in a commentary published Tuesday in the New England Journal of Medicine, is inspired by the age-old concept of variolation, the deliberate exposure to a pathogen to generate a protective immune response. First tried against smallpox, the risky practice eventually fell out of favor, but paved the way for the rise of modern vaccines.
Masked exposures are no substitute for a bona fide vaccine. But data from animals infected with the coronavirus, as well as insights gleaned from other diseases, suggest that masks, by cutting down on the number of viruses that encounter a person’s airway, might reduce the wearer’s chances of getting sick. And if a small number of pathogens still slip through, the researchers argue, these might prompt the body to produce immune cells that can remember the virus and stick around to fight it off again.
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Experiments in hamsters have hinted at a connection between dose and disease. Earlier this year, a team of researchers in China found that hamsters housed behind a barrier made of surgical masks were less likely to get infected by the coronavirus. And those who did contract the virus became less sick than other animals without masks to protect them.
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But despite decades of research, the mechanics of airborne transmission largely remain “a black box,” said Jyothi Rengarajan, an expert in vaccines and infectious disease at Emory University who was not involved in the commentary.
That is partly because it is difficult to pin down the infectious dose required to sicken a person, Dr. Rengarajan said. Even if researchers eventually settle on an average dose, the outcome will vary from person to person, since factors like genetics, a person’s immune status and the architecture of their nasal passages can all influence how much virus can colonize the respiratory tract.
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(Note: the online version of the story has the date Sept. 8, 2020, and has the title “A New Theory Asks: Could a Mask Be a Crude ‘Vaccine’?”)