New Study Strengthens the Argument for N95 Masks

F.J. Thomas

Sarasota, FL ( – A recent analysis financially backed by the World Health Organization (WHO) that reviewed 172 observational studies strengthens the argument for N95 and respirator type masks. The analysis cross referenced and analyzed data from 44 comparative studies on SARS, Middle East respiratory syndrome (MERS), COVID-19, and betacoronaviruses. The report, led by Derek K Chu, MD and colleagues, was published in the Lancet this week.

Although WHO has stopped just short of stating that the corona virus is “airborne” there are several studies that suggest that could be exactly the case. One study in particular showed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was more tolerable of airborne distribution than other forms of coronavirus. In fact, the study found viable virus in the air 16 hours after it had been distributed in aerosol form, and that the virus was able to maintain infectivity the entire time.

The studies suggesting that SARS-CoV-2 has a proclivity to airborne distribution challenges the 6 foot rule originating from studies in the 1930’s and 1940’s. While the Centers for Disease Control and Prevention recommends a 6 foot minimal distance, WHO only recommends 3 feet for social distancing. Because of the WHO recommendation, this particular analysis focuses on a 3 foot minimal distance.

The report shows that risks decreases by 82 percent with a social distance of 3 feet. However, the study also suggests that for every increase in distance by 3 feet the rate of protection more than doubled.

The use of masks reduced infection risk by 85 percent in the community, with a 95 percent rate in a healthcare setting. Researchers attributed the difference in results to the predominate use of N95 masks in healthcare settings. When compared to other masks, N95 and respirator type masks were 96 percent effective, while other masks including surgical masks were only 77 percent effective. The researchers state that these results suggest an N95 mask should be the minimal requirement for workers at risk.

Another notable result in the analysis, especially in light of possibility of airborne transmission, is that eye protection reduced infections by 78 percent.

The researchers also suggested that multi-layer masks are more effective than single layer masks. The researchers advocated using a water resistant fabric with multiple layers. Additionally, they advised close attention to facial fit as well as a key component to avoiding transmission.

The full study is available on the Lancet website with commentary written by C Raina MacIntyre and Quanyi Wang.

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