Recent research shows that face masks reduce public transmission of COVID-19 and suggests widespread indoor masking during pandemics caused by airborne viruses, a new study says.
Five medical specialists published the privately funded study Tuesday in JAMA Network Open. They reviewed 47 top research papers that used seven different methods to study the effectiveness of masking around the globe between 2020 and 2022.
Researchers noted that laboratory model studies, randomized clinical trials, meta-analyses, cohort studies, case-control studies, cross-sectional studies and ecologic studies all provided direct evidence “demonstrating the association of face mask use in the community and of mask mandates with reduced spread of SARS-CoV-2.”
Consistent masking reduced the likelihood of spreading COVID by about 30%-70% in most of the studies, with rates highest where people wore “high quality masks” more consistently indoors, said Tom Frieden, a co-author of the study who served as director of the Centers for Disease Control and Prevention under President Barack Obama.
“Because much of COVID — approximately half — is spread before people feel sick, widespread masking indoors when COVID is spreading can be an effective way to reduce spread,” Dr. Frieden, an infectious disease specialist who now leads the public health advocacy group Resolve to Save Lives, told The Washington Times.
In the study, the five researchers noted that these findings challenge the disagreements of masking critics who focused only on randomized trials during the pandemic, which they said “are limited in number, scope, and statistical power.”
“Many effective public health policies have never been assessed in randomized clinical trials; such trials are not the gold standard of evidence for the efficacy of all interventions,” the researchers wrote.
Their review of the 47 studies found surgical masks had higher rates of preventing the spread of airborne pathogens than cloth masks, and high-filtration N95 or KN95 masks were more effective than both.
How well a mask fit and how consistently people wore it also influenced how well it stopped people from spreading respiratory illnesses to others.
However, the researchers noted that “whether masks work is a different question from whether mask mandates work,” which they said depends on several factors and “can be challenging to demonstrate.”
While high rates of indoor masking during the early pandemic may have reduced infection and death numbers in some parts of Asia where masks were already commonplace, the doctors wrote that “a mandate is unlikely to have an impact” if few people obey it.
“Masks don’t protect people if they aren’t worn and may not protect well if they aren’t worn properly,” Dr. Frieden told The Times.
For more information, visit The Washington Times COVID-19 resource page.
• Sean Salai can be reached at ssalai@washingtontimes.com.