In a mid-December comment in Cell magazine on the science of wearing masks, two experts wrote that a way for the public to obtain “maximum protection” from masks was “to wear a cloth mask firmly on top of a surgical mask where the surgical mask acts as a filter and the tissue mask provides an additional layer of filtration, improving fit. ”
When you combine multiple layers, “the air has to follow this tortuous path,” said Virginia Tech’s virus transmission expert Linsey Marr and one of the authors of the Cell comment to The New York Times. “The great things [like virus particles] carrying will not be able to follow those twists and turns. “
(Another alternative suggested by the authors: cloth mask with pocket that can be filled with filtering material, such as those found in vacuum bags.)
“I recommend that people select masks based on the activity and the risk level of that activity. If walking outdoors with a friend, a simple 2 or 3 layer mask is enough, ”said Joseph Allen, professor of exposure assessment science at the Harvard TH Chan School of Public Health.
“If you go to the supermarket or are an essential worker who comes in contact with a lot of people, I recommend wearing a cotton mask over a surgical mask that can capture more than 90% of respiratory aerosols,” said Allen on Friday. in an email. “I also like this approach because most people don’t have access to [high-filtration N95 masks], but they have access to a cotton and surgical mask. “
On Friday, Dr. Dara Kass, associate professor of emergency medicine at Columbia University Irving Medical Center in New York, coronavirus-treated patients this spring and she herself had the virus, she declared her support for duplication. “If you’re in a high-risk area and haven’t been vaccinated, double-masking is the best option,” she tweeted.
Her tweet included a photo of Pete Buttigieg, nominated by President Biden as transport secretary, and her husband, Chasten, wearing what appeared to be a double mask at the opening. “Always proud to see@PeteButtigieg and @Chasten best practice model, ”she wrote.
Former US food and drug manager Scott Gottlieb said on Monday in a tweet: “We also need to be more vigilant about masking. The quality of the mask is more important now. N95 better or double mask. “
What can we do? We are in a race against time to obtain maximum protective immunity in the population and protection against continuous spread. The vaccine is our only tool. We also need to be more vigilant about masking. The quality of the mask is more important now. N95 best, or double masking.
– Scott Gottlieb, MD (@ScottGottliebMD) January 17, 2021
The US Centers for Disease Control and Prevention website does not mention double masking. The official recommendation is that people wear a mask of two or more layers of tightly woven fabric that you can’t see through, said CDC spokesman Brian Katzowitz. He noted, however, that people who only have single layer fabric masks can fold them to obtain the “recommended level of protection”.
Dr. Paul Sax, clinical director of the Infectious Diseases Division at Brigham and Women’s Hospital, said something similar, saying that the double mask made sense if a person only had thin tissue masks.
Other experts said the new double mask methods could help, but noted that there was still no research on the subject.
“Double masks are well-intentioned, but have not been studied,” said Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine.
“If you want to wear a double mask, that’s fine,” he said in a telephone interview on Friday. “It makes good sense that you have double barriers … but make sure you put on the first mask correctly.”
“I think the main thing is to make so many Americans wear any mask and wear it correctly, which means even masking their nose,” he said.
Dr. Abraar Karan, a global health and internal medicine physician at Brigham and Women’s Hospital, who openly advocated for better masks, said that “all of these solutions are important”, but also warned that double masking was not a certain thing.
“While MacGyvering his own mask at home is tempting and can provide protection, there is really no guarantee,” he said in a telephone interview on Friday.
He noted that, for any mask, a good fit is the key to obtaining the best filtration, and that the Cell authors cited a better fit as one of the reasons for the double mask, with a cloth mask “right over” the blue surgical mask.
Karan also said that interest in the double mask highlighted the lack of high filtration masks available to the public.
“The reason people are trying to create these solutions is that we don’t have access to the masks that we know are already certified for healthcare professionals,” he said.
Karan and co-authors, in an opinion column earlier this month at STAT, called for a national initiative to produce and distribute high-filtration masks like the N95s used by healthcare professionals.
“Ideally, a set of masks would be sent to every U.S. family every month – the costs of doing so are negligible compared to the impact of the pandemic on lives and the economy,” said the column, asking President Biden to use Defense Production Take action to intensify mask production.
Sax said he also supported the provision of free high quality masks or reduced prices.
Good masks are essential, experts say. A mask that is very effective in blocking the transmission of the virus by the user and protecting it from transmission by others will prevent the virus from spreading.
This “essentially makes the user a dead end for the virus,” said Karan in the interview.
Now that the highly transmissible variant from the UK has emerged in the United States, effective masks are even more important, he said.
Globe news agency material was used in this report.
Martin Finucane can be reached at [email protected].