Theoretically, it seems masks can and do allow for variolation. Because masks simply can’t and don’t block all the viruses that are surrounding us. You’d have to be a fool to believe otherwise. And yes, I know there are lots of fools around. It does also appear there is an observational correlation between mask mandates and increased Covid positive tests. Including here in Canada. I've certainly noticed it! And mentioned the correlation on more then one occasion here at the blog.Most recently:
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Break the Mask Psychosis: Germany, In Spite of Mandatory Mask Policy, Has Soaring Infection Rates
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Breaking the Mask Psychosis: Spain's Strict Mask Policy- results in increased Covid cases
The theory, “ 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. ( Herd Immunity) First tried against smallpox, the risky practice eventually fell out of favor, but paved the way for the rise of modern vaccines.(Also risky)
"SARS-CoV-2 has the protean ability to cause myriad clinical manifestations, ranging from a complete lack of symptoms to pneumonia, acute respiratory distress syndrome, and death. Recent virologic, epidemiologic, and ecologic data have led to the hypothesis that facial masking may also reduce the severity of disease among people who do become infected.3 This possibility is consistent with a long-standing theory of viral pathogenesis, which holds that the severity of disease is proportionate to the viral inoculum received. Since 1938, researchers have explored, primarily in animal models, the concept of the lethal dose of a virus — or the dose at which 50% of exposed hosts die (LD50). With viral infections in which host immune responses play a predominant role in viral pathogenesis, such as SARS-CoV-2, high doses of viral inoculum can overwhelm and dysregulate innate immune defenses, increasing the severity of disease. Indeed, down-regulating immunopathology is one mechanism by which dexamethasone improves outcomes in severe Covid-19 infection. As proof of concept of viral inocula influencing disease manifestations, higher doses of administered virus led to more severe manifestations of Covid-19 in a Syrian hamster model of SARS-CoV-2 infection.4If the viral inoculum matters in determining the severity of SARS-CoV-2 infection, an additional hypothesized reason for wearing facial masks would be to reduce the viral inoculum to which the wearer is exposed and the subsequent clinical impact of the disease. Since masks can filter out some virus-containing droplets (with filtering capacity determined by mask type),2 masking might reduce the inoculum that an exposed person inhales. If this theory bears out, population-wide masking, with any type of mask that increases acceptability and adherence, might contribute to increasing the proportion of SARS-CoV-2 infections that are asymptomatic.
The typical rate of asymptomatic infection with SARS-CoV-2 was estimated to be 40% by the CDC in mid-July, but asymptomatic infection rates are reported to be higher than 80% in settings with universal facial masking, which provides observational evidence for this hypothesis. Countries that have adopted population-wide masking have fared better in terms of rates of severe Covid-related illnesses and death, which, in environments with limited testing, suggests a shift from symptomatic to asymptomatic infections. Another experiment in the Syrian hamster model simulated surgical masking of the animals and showed that with simulated masking, hamsters were less likely to get infected, and if they did get infected, they either were asymptomatic or had milder symptoms than unmasked hamsters. 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).
That’s a straightforward correlation between mask wearing and widespread infection with Covid-19. Asymptomatic infections 81 percent masked vs 20 percent unmasked? Masks help to spread the infection.
To test our hypothesis that population-wide masking is one of those strategies, we need further studies comparing the rate of asymptomatic infection in areas with and areas without universal masking. To test the variolation hypothesis, we will need more studies comparing the strength and durability of SARS-CoV-2–specific T-cell immunity between people with asymptomatic infection and those with symptomatic infection, as well as a demonstration of the natural slowing of SARS-CoV-2 spread in areas with a high proportion of asymptomatic infections.
Ultimately, combating the pandemic will involve driving down both transmission rates and severity of disease. Increasing evidence suggests that population-wide facial masking might benefit both components of the response.
Evidence suggests that wide spread mask wearing will spread the virus further. Or you wouldn't have such an increased rates of asymptomatic infectionsFinally from NYT's
“You can have this virus but be asymptomatic,” said Dr. Monica Gandhi, an infectious disease physician at the University of California, San Francisco, and one of the commentary’s authors. “So if you can drive up rates of asymptomatic infection with masks, maybe that becomes a way to variolate the population.”
Variolate = Herd Immunity sans the vaccine