Variolation and Mitigation: How Mask Wearing Might Lessen COVID-19 Severity

By: Sara Verschleisser  |  October 29, 2020

By Sara Verschleisser, Science and Technology editor

Since the fight against COVID-19 began, masking has been a point of contention throughout the United States. Due to the politicization of masking, the science supporting its necessity and efficacy has been ignored, misrepresented, and misunderstood. This has led to a mishandling of the COVID threat, and much greater losses than may have occurred if scientific evidence was respected. 

Masks have been clearly found to lower SARS-CoV-2 transmission rates, especially as COVID-19 often arises as an asymptomatic disease that can be passed without one’s knowledge of their own illness. Much of the anti-mask movement surrounds current research, which shows that masks protect others much more than oneself. While this is only a part of the heavily politicized movement, it is a weighted factor. To many, the sacrifice of wearing a mask is too big a concession in order to keep others safe. Recent theories, however, including that of two University of California researchers, suggest that masks could be keeping the mask wearer safe as well-by creating a form of variolation.

Dr. Monica Gandhi and Dr. George W. Rutherford published an article on their theory in the New England Journal of Medicine, titled “Facial Masking for Covid-19 — Potential for “Variolation” as We Await a Vaccine.” Their theory surrounds the concept of viral dosage. Since the 1930s, researchers have been studying the connection between the amount of viral inoculum received and the severity of the host’s disease. This research is grounded in the LD50, or the dose at which a virus is lethal for 50% of exposed hosts. As SARS-CoV-2 and many other viruses directly interact with the immune system, high doses of the virus can overwhelm the system’s defenses before it can start to fight back. Because the host loses its immune defenses, the severity of the disease can increase. This viral theory has already been shown to hold true for SARS-CoV-2 in experiments with Syrian hamster models. If, on the other hand, the viral dosage is low, the host can still become infected but is much more likely to be asymptomatic, as their immune system has more time to respond to the virus before becoming overwhelmed.

According to Dr. Gandhi and Dr. Rutherford’s theory, masks may function as a method for lowering the viral dosage. Universal masking, therefore, won’t only lower the total number of cases, but also lower the number of severe cases. Preliminary analysis of population-wide masking has noted an increase in the percentage of infections which are asymptomatic. As Gandhi and Rutherford’s article references, asymptomatic rates in mid-July were only 40% of cases according to the CDC, but in settings with universal masking, this has risen to 80% of cases. Countries with universal masking have also fared better in terms of rates of severe illness and deaths, suggesting more asymptomatic infections. Mimicked mask-wearing in the Syrian hamster studies also saw fewer infections overall and more asymptomatic cases.

Gandhi and Rutherford compare the use of masks to variolation. Variolation was an early version of smallpox inoculation where people were purposely infected with small amounts of the smallpox, in order to prevent people from later developing a more severe infection and dying. While people still got sick, variolation succeeded in lowering smallpox mortality from 30% of those infected to 1-2%. 

The goal, of course is not just to lower the toll of a virus but to eliminate it. However, in the meantime, masks used as variolation may be an effective tool to lower the rates of severe disease and increase population-wide immunity at the same time. Reinfection, as of research in early September, appears to be rare and less severe, suggesting that allowing asymptomatic infections may be beneficial for the population’s herd response. 

However, more research into the idea of using masks as variolation must be done. Gandhi and Rutherford outline the concerns that must be settled before masks as variolation can really be proposed as a public health tactic. Further studies on the rates of asymptomatic infection in areas with population-wide masking vs. those with low masking must be carried out. The immunity of previously infected individuals and how these individuals and the general community respond to further infections must be researched as well. 

Many researchers do caution against placing too much weight in this theory before it’s more supported, especially from a public health outlook. Letters to the Editor addressing Gandhi and Rutherford’s article point out the danger in using the term ‘variolation,’ due to its association with risk, and the large difference between the smallpox and SARS-CoV-2 viruses. These researchers caution against relying on this theory until the idea is more researched, and until there is more evidence to suggest that SARS-CoV-2 can be controlled in this way.

Because so much is still unknown about the long term effects of infection, masks as variolation isn’t yet a viable option for a public health COVID-19 response. However, the available research and the medical support for this theory already provides an excellent reason to keep masking. It also suggests an additional reason, besides better treatments, for the decline in rates of hospitalizations and deaths that is being seen in many mask wearing populations, even with an increase in cases. 

Wearing a mask doesn’t hurt; it only helps. As the weather gets cold again, and people are forced indoors, please remember to wear a mask, be COVID safe, and protect both yourself and those around you.