100 Prominent Health Officials Sign Open Letter To Make Masks Mandatory

More than 100 prominent health officials have signed an open letter urging governors to make wearing cloth masks in public mandatory, citing a “preponderance of evidence” they greatly reduce the transmissibility of COVID-19.

The letter was written by Jeremy Howard, a research scientist at the University of San Francisco who, along with a team of other researchers, has studied the efficacy of masks at length. Howard also wrote an opinion piece in Thursday’s USA Today about the letter’s recommendation.

Just how effective would mass mask-wearing be? Research suggests it could effectively halt the spread of the virus ― but only if at least 80%, and ideally all people, wear them.

“The preponderance of evidence, in both laboratory and clinical settings, indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets,” the letter notes. “The decreased transmissibility could substantially reduce the death toll, other harms to public health, job losses and economic losses. The cost of such masks is very low by comparison.

“Modeling suggests that widespread public mask use, in conjunction with other measures, could bring [down] the effective reproduction number ... thus halting the growth of the pandemic.”

By now, those “other measures” should be familiar to most people: proper hand hygiene, social distancing, testing and contact tracing.

A study published last month in the New England Journal of Medicine found a cloth mask can stop more than 90% of the droplets that can spread the coronavirus. But that’s only the case when the mask captures droplets at the source, when worn by a person who’s infected. Since not all infected people show symptoms, everyone should wear a mask.

The letter’s co-signers include a trove of noted academics, researchers and medical professionals, including Nobel Prize winners, medical school professors and editors of prestigious science and medical journals.

“We ask that government officials require cloth masks to be worn in all public places, such as stores, transportation systems, and public buildings as soon as possible,” the open letter says. “This action will prevent people who are infectious from unknowingly spreading the disease.”