Masks may reduce viral dose, some experts say

Researchers say there is growing evidence that masks help safeguard people who wear them by reducing the severity of symptoms or even preventing infection. Monica Gandhi, MD, MPH, an infectious disease physician at the University of California, San Francisco, and colleagues wrote in a paper that different types of masks “block virus to a different degree, but they all block the virus from getting in.” Moreover, if any virus particles are able to infiltrate the mask, the disease might still be milder, according to the researchers, whose paper is set to be published in the Journal of General Internal Medicine. Based on animal experiments and observations of various events during the COVID-19 pandemic, they say people wearing face coverings will take in fewer coronavirus particles, which makes it easier for their immune systems to deal with the pathogen. Tsion Firew, MD, an emergency physician at Columbia University who was not involved in the work, warns that the connections between masking and milder disease have not yet been proved as cause and effect. Still, the paper “reiterates what we say about masks. It’s not just a selfless act,” she asserts. Gandhi says the way for people to curb the pandemic is to assume they are infected, “even if you feel right as rain.”