There are reports that the US Centers for Disease Control and Prevention (CDC) may recommend that those who can wear a higher standard of mask when in public – specifically those KN95 and N95 masks that have become increasingly popular in the past two years.
According to The Washington Post, an unnamed government official stated that “the agency is actively looking into updating its recommendations for KN95 and N95 Masks in light of Omicron”, adding: “We know that these masks provide better filtration”.
The surge in cases puts pressure on the CDC and the Biden administration to adjust their Covid-19 strategy on multiple fronts, from home test provision to isolation requirements to vaccination mandates. Since the pandemic started, the question of which masks provide the best protection has been a factor in the politics of masking.
What are the reasons for the CDC’s recommendation of these masks specifically? What makes them better than cloth masks, which are used by the vast majority of people, and how can they be reused given that they’re relatively expensive and sometimes hard to obtain?
N95 and KN95 masks work by covering the face tightly and filtering air using layers of material designed to trap very small particles, something that common cloth or disposable masks cannot do nearly as well.
N95 masks are the recommended high-standard face covering for healthcare workers in the US. N95s approved by the CDC block up to 95% of airborne particles if they are fitted properly to form a tight seal around the face. The mask can be harder to breathe through than a standard mask, and they are also more expensive.
On the other hand, KN95s are more widely available and cheaper. They weren’t approved for medical use in the US before the pandemic, but have since been authorised as a replacement for N95s. While they are approved by various international standards, the CDC warns that many of those standards do not include quality requirements – and, even more importantly, that as many as 60% of those available in the US are counterfeit.
How do you reuse them?
According to CDC guidelines, N95 masks should not be reused under normal circumstances. In the first year of the pandemic, the CDC issued guidelines for the reuse of masks and personal protective equipment because of the challenges in obtaining disposable high-grade masks.
A study published in 2020 found that the best way to reuse N95s was to rotate them over several days, heat them at 70 degrees Fahrenheit for an hour, or even boil them. It is not recommended to wash them with soap and water or alcohol.
However, this refers to masks worn by healthcare workers in high-risk settings. In consideration of people who wear masks in everyday life and can follow other distancing precautions, experts suggest leaving a used mask in a brown paper bag for one or two days. This will allow the mask to dry out and prevent any virus that remains on it from infecting anyone nearby.