With the more transmissible Delta the most prevalent strain circulating right now, and the onset of colder weather necessitating more time spent in public indoor spaces, choosing the most effective mask is more important than ever. And a new study has found that surgical and cloth masks don’t make the grade. Findings published in the journal Clinical Infectious Diseases say that the dominant Delta variant emits up 100 times more aerosol particles than the original Alpha virus. Even if you are vaccinated, breakthrough cases are occurring so you may want to rethink your mask choice.
According to LADDERS, the Delta strain is 60% more transmissible than previous versions of the COVID virus. That means that loose-fitting cloth masks and surgical masks may reduce your risk of airborne infection by 50%, but wearing N95s and KN95s without valves are your best bet.
Experts say that the woven material of cloth masks isn’t as effective in filtering particles as the nonwoven polypropylene of N95s. The new study conducted by researchers at the University of Maryland found that strains that are more contagious have a higher viral load. Researchers discovered that with the newer strains, exhaled aerosols are increasing.
Face covering helps protect the wearer from inhaling viruses – and prevents exhaled viruses from reaching others, says LADDERS, adding that not even N95 or KN95 masks are perfect, so adding social distancing can further help to reduce your risk of infection.
“SARS-CoV-2 is evolving toward a more efficient aerosol generation and loose-fitting masks provide significant but only modest source control,” said the authors of the study. “Therefore, until vaccination rates are very high, continued layered control and tight-fitting masks and respirators will be necessary.”
N95 and KN95 face coverings are designed to fit snugly over the face, which allows them to filter at least 95% of airborne particles, says LADDERS. Cloth masks and surgical masks are not as effective against Delta’s high viral load.
When wearing a cloth mask, two layers are better than one, however. According to Business Insider, research has shown that that a two-layered fabric mask is superior to a single-layered cloth face covering, so doubling up is recommended. Experts even suggest using three layers to help filter out potentially infectious respiratory droplets and aerosols. A study published in April determined that when two layers of 600 thread-count cotton were added to a layer of another common fabric, such as silk or chiffon, the mask was even more efficient in filtering out particles. However, the study authors warned that if any mask is ill-fitting and has gaps, this can result in a 60% decrease in filtration efficiency.
“The take-home messages from this paper are that the coronavirus can be in your exhaled breath, is getting better at being in your exhaled breath, and using a mask reduces the chance of you breathing it on others,” said study co-author Dr. Jennifer German, assistant clinical professor at the University of Maryland and one of the study’s co-authors.