The first time, the Center for Disease Control and Prevention (CDC) has advised that even seemingly healthy people wear masks over their mouths and noses when venturing out of their homes into places where it is not easy to maintain distance from other people. There is however still major debate over just how much masks – particularly the Face Masks For Coronavirus that the CDC recommends for the public – can slow the spread of SARS-CoV-2, the virus that causes COVID-19.
Researchers, writing in two new papers, attempt to tackle the efficacy of masks, one more rigorously compared to other, and come to differing conclusions. One study examined the effect of masks on seasonal coronaviruses (which cause many cases of the common cold) and found that surgical masks are helpful at reducing how much virus a sick person spreads. One other looked particularly at SARS-CoV-2 and found no effect of either surgical or fabric masks on reducing virus spread, only had four participants and used a crude way of measuring viral spread.
The base line, experts say, is the fact that masks might help keep individuals with COVID-19 from unknowingly passing across the virus. However the evidence for the efficacy of surgical or homemade masks has limitations, and masks aren’t the most significant protection from the coronavirus.
“Placing a face mask on will not mean which you stop another practices,” said May Chu, a clinical professor in epidemiology at the Colorado School of Public Health on the Anschutz Medical Campus who was not involved in either new study. “It will not mean you get nearer to people, it can not mean you don’t need to wash your hands as much and you also can touch your face. All that still is within place, this is just an add-on.”
Face mask basics
Recommendations about Masks For Coronavirus can easily get confusing, because all masks usually are not made equal. The N95 mask effectively prevents viral spread. These masks, when properly fitted, seal closely towards the face and filter out 95% of particles .3 microns or larger. But N95 masks have been in serious shortage even for healthcare professionals, that are subjected to the highest degrees of SARS-CoV-2 and are most needing the strongest protection against the virus. They’re also difficult to fit correctly. For all those reasons, the CDC fails to recommend them for general use.
Because of shortages, the CDC also will not recommend surgical masks for that general public. These masks don’t seal from the face but do include non-woven polypropylene layers that are moisture resistant. In a surgical mask, about 70% of the outside air moves with the mask contributing to 30% travels round the sides, Chu told Live Science. Because of this, they don’t offer just as much protection as N95s.
That leaves fabric masks, which currently are suitable for general use by the CDC. Fabric masks also allow air in round the sides, but lack non-woven, moisture-repelling layers. They impede just about 2% of airflow in, Chu said.
All of this leakage in surgical and fabric masks are why public health officials generally don’t believe that wearing a mask prevents anyone from catching a virus that is already floating around in the environment. Airflow follows the way of least resistance, said Rachael Jones, an associate professor of family and preventive medicine in the University of Utah who had been bevggk involved in the new research. If viral particles are nearby, they may have a fairly easy path around a surgical or fabric mask. And in the case of any fabric mask, wearers may well be wafting in particles small enough to flow right through the fabric.
But have you thought about the other way around? When the wearer of Face Masks For Coronavirus coughs or sneezes, the barrier might be sufficient to contain a lot of that initial jet of grossness – even if you will find gaps inside the fabric or across the sides. That’s what the new mask studies aimed to address: Whether surgical or fabric masks did a great job of containing viruses.