Face masksConfronting the Notion that Face Masks Reduce COVID “Dose”
When two physicians at the University of California at San Francisco published a commentary in the New England Journal of Medicine (NEJM) on Sep 8 proposing to resurrect the 18th century practice of variolation using face coverings to prevent severe COVID-19 and confer immunity, the Internet lit up with headlines such as “Coronavirus: Another reason for that mask: You’ll get less sick.” Concerned that the piece, its positioning in a top medical journal, and the resulting media coverage would embolden people to abandon physical distancing and other public health measures in favor of only wearing face coverings, scientists warned against the practice.
When two physicians at the University of California at San Francisco published a commentary in the New England Journal of Medicine (NEJM) on Sep 8 proposing to resurrect the 18th century practice of variolation using face coverings to prevent severe COVID-19 and confer immunity, the Internet lit up with headlines such as “Coronavirus: Another reason for that mask: You’ll get less sick.”
The paper, written by Monica Gandhi, MD, MPH, and George Rutherford, MD, suggested that face coverings, in the absence of a vaccine, could reduce the inhaled dose of coronavirus by filtering some virus-containing droplets, leading to asymptomatic or mild disease and stimulating T- and B-cell immunity.
Concerned that the piece, its positioning in a top medical journal, and the resulting media coverage would embolden people to abandon physical distancing and other public health measures in favor of only wearing face coverings, scientists warned against the practice in two letters to the editor in the same journal on Oct 23.
Reviving an Ancient Practice
The inspiration behind Gandhi and Rutherford’s piece was variolation, the practice of inoculating healthy people with variola, the virus that causes smallpox, to give them a lower dose than would be inhaled, producing mild disease and stimulating immunity. While variolation worked in some people, others died of their infections, and it was abandoned after a vaccine became available in 1796. Gandhi and other colleagues also published a paper on the topic in July in the Journal of General Internal Medicine.
However, Angela Rasmussen, PhD, associate research scientist at the Center for Infection and Immunity at Columbia University and coauthor of the first letter, along with Kevin Escandon MD, of Universidad del Valle in Colombia, and Saskia Popescu, PhD, of George Mason University, said the proposal is based on faulty assumptions about an emerging coronavirus about which much is yet unknown.
“We don’t know the role that T cells play in determining disease severity,” Rasmussen said, let alone whether asymptomatic or mild disease generates the long-lasting, robust antibody responses required for durable immunity.
A Hypothesis, Not Evidence
Publishing a hypothesis—without describing the experiments that would need to prove or disprove it—in a prominent journal like NEJM sends the message that the concept has been borne out by evidence, Rasmussen said, adding that the paper would have been acceptable had it been framed as only a hypothesis.
