New research shows that both slightly used and expired N95 masks can still block coronavirus particles as new ones do, and may even perform better than surgical masks.
The World Health Organization strongly advises the wearing of face masks, whether it is surgical, homemade, or N95 masks, as a measure to mitigate the spread of coronavirus. But do all types of face mask yield the same effect one needs to protect himself from contracting coronavirus?
In a new study published by JAMA Internal Medicine, researchers found that N95 masks provide better protection compared to surgical masks, particularly in a healthcare setting.
N95 masks perform better than surgical masks
Conducted by the researchers of the University of North Carolina at Chapel Hill, the study includes testing of 29 types of masks to a male volunteer. In contrast, six of the most commonly used medical masks were tested on a female volunteer. The test, however, did include non-medical masks such as bandanas or cotton-based masks.
To test each of them, the researchers separately sent the volunteers to stay in a chamber filled with aerosolized particles of salt that are the same size as the SARS-CoV-2, the virus that causes COVID-19.
Volunteers were then asked to perform movements healthcare professionals typically do during their duties after three minutes of exposure, including twisting the head from side to side, bending over, reading, and moving the head up and down.
In the process, they found out that N95 masks provided almost complete protection while surgical masks performed the worst.
The data states that surgical mask with ear loops blocked nearly 40% of particles for the male volunteer. But for the female volunteer, it provided below 27% only. The filtration ability of surgical masks with tie at the back of the head, however, was nearly 72%—far better than the one with ear loops.
On the flip side, all types of N95 (new, expired, and even the ones that slightly used) provided better protection compared to surgical masks with over 95% filtration rate. Remarkably, all the said variations did not yield less than 96.8% protection.
The study may be far from perfect
Separately, the researchers noted that the study might be far from perfect, specifically with surgical masks.
The team explained that face coverings’ fitting vary from person to person, and such aspects could massively affect its filtration ability, unlike N95 masks that fit well regardless of the person’s head shape or face.
In a commentary that is included in the study, Harvard Medical School infectious-disease specialists Rochelle Walensky and Caitlin Dugdale said:
“Importantly, no documented SARS-CoV-2 outbreaks have been linked to settings in which surgical masks were assiduously used in lieu of N95 masks, which suggests that even if airborne transmission is a considerable contributor to SARS-CoV-2 transmission, surgical masks are likely sufficient to prevent it.”
Still, one thing that impressed the researchers is that even N95 masks that are expired and are slightly used can always protect health workers from contracting the virus, provided that those that were reused were adequately sanitized.