A new theory asks: Can a mask be a crude ‘vaccine’?

As the world awaits the arrival of a safe and effective coronavirus vaccine, a team of researchers have come forward with a provocative new theory: that the mask can help severely 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 old-fashioned concept of variability, from the deliberate exposure of a pathogen to produce a protective immune response. At 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 sonar. But data from coronovirus-infected animals, as well as glowing insights from other diseases, suggest that masks can reduce the likelihood of becoming ill, by cutting the number of viruses a person encounters through the airway. And if a small number of pathogens still slip through, the researchers argue, these can induce the body to produce immune cells that can miss the virus and surround it to fight back again Can stick.

“You may have this virus, but may be asymptomatic,” said Dr., an infectious disease physician at the University of California, San Francisco. Monica is one of the authors of Gandhi and commentary. “So if you can drive rates of asymptomatic infection with masks, maybe it’s a way to isolate the population.”

This does not mean that people should intentionally donate a mask to vaccinate themselves with the virus. “It is not a recommendation at all,” Dr. Gandhi said. “Neither are pox parties,” he said, referring to social ceremonies that affect healthy and sick people.

The theory cannot be directly proved without clinical trials comparing the results of those with those in the presence of coronovirus to those that are unmasked – an inelastic experimental setup. And while outside experts were intrigued by the theory, they were reluctant to embrace it without much data, and advised careful interpretation.

“It feels like a leap,” Saskia Popescu, an infectious disease epidemiologist based in Arizona, did not include in the comment. “We don’t have much to support it.”

Taken incorrectly, this idea may create a sense of falsehood with decency, possibly putting them at greater risk than before, or perhaps even raising the misconception that face covering is completely useless against coronovirus , Because they cannot present to the wearer. Impermeable to infection.

“We still want people to follow all other prevention strategies,” Drs. Popesu said. This means being alert to crowd avoidance, physical disturbances and hand hygiene – behaviors that overlap in their effects, but cannot replace each other.

The coronovirus variogram theory rests on two assumptions, which are difficult to prove: low doses of the virus cause severe illness, and this mild or asymptomatic infection may induce long-term protection against subsequent bouts of the disease. Although other pathogens have offered some precedents for both concepts, the evidence for coronovirus is scant, as scientists have only had the opportunity to study the virus for a few months.

Experiments in the hamster have hinted at the association between dose and disease. Earlier this year, a team of researchers in China found that hamsters behind a barrier made of surgical masks were less likely to be infected with coronaviruses. And those who contracted the virus became less ill than other animals without masks to protect them.

Some observations in humans support this trend. In crowded settings where there is widespread use of masks, the rate of infection decreases. And although face coverings may not block all inbound virus particles for all people, they appear to be associated with less disease. Researchers have found largely silent, disease-prone outbreaks ranging from cruise ships to food processing plants, mostly all masked people.

Data linking symptoms to doses have been gathered for other microbes that attack the human airway, including influenza viruses and bacteria that cause tuberculosis.

But despite decades of research, the mechanics of airborne transmission remain largely “a black box”, said Jyoti Rengrajan, an expert in vaccines and infectious disease at Emory University who was not involved in the remarks.

This is partly because it is difficult to reduce the infectious dose required for a person to drown, Drs. Rengarajan said. Even if researchers eventually settle on an average dose, the results will vary from person to person, as factors such as genetics, a person’s immune status, and the architecture of their nasal passages can all affect How much the virus can colonize the respiratory tract.

And confirming the second half of the theory of violations – that masks allow entry into the virus just enough to prime the immune system – can be very difficult. Although several recent studies have pointed to the possibility that mild cases of covid-19 may provoke a strong immune response to coronovirus, durable protection may not be proven until researchers resolve them months later Or do not collect data on infection for years.

Overall, the theory “has some properties”, said Angela Rasmussen, a virologist at Columbia University, who was not included in the comment. “But I’m still very confused.”

It is important to remember, she said, that vaccines are inherently less dangerous than actual infections, which is why practices such as variolation (sometimes called inoculation) eventually become outdated. Prior to the discovery of vaccines, doctors created smallpox stains or pieces of pus by rubbing into the skin of healthy people. The resulting infections were generally less severe than the cases of smallpox, but “people certainly succumbed to smallpox and died of variolation,” Dr. Rasmussen said. And vaccination, unlike vaccines, can make people contagious to others.

Dr. Gandhi accepted these limitations, noting that the principle should be considered nothing more than this – a theory. Still, he said, “When we are waiting for the vaccine, why not increase the chances of getting sick and not having some immunity?”