Over-60s should use medical-grade masks and all others three-layer fabric ones, health body says

People over 60 or with health issues should wear a medical-grade mask when they are out and cannot socially distance, according to new guidance from the World Health Organization, while all others should wear a three-layer fabric mask.

The announcement on Friday marks a significant change of stance by the WHO, which until now has been reluctant to advocate the wearing of masks by the public because of limited evidence that they offer protection.

The health body’s new guidance document says the over-60s and people with underlying health conditions should wear medical masks in “settings where physical distancing cannot be achieved” because of “increased risk of infection and/or negative outcomes”.

The WHO said people should be advised to wear masks not only on buses and trains but also wherever physical distancing may be hard – in grocery stores, at work, at social gatherings, at mass gatherings and in closed settings, including schools, churches, mosques and other places of worship.

We know that by wearing masks, we can help reduce the transmission of COVID-19, and we know that not every type of face mask is equally good at blocking viral droplets when we cough, sneeze, talk – or even simply breathe. But how can we really know for sure?

New research from scientists at Duke University shows you don’t actually need all that much to devise a test. In a proof-of-concept study, they cobbled together a simple, low-cost laser device, and conducted an experiment comparing 14 different types of masks and face coverings.

“Surgical masks are commonly worn by medical personnel and have received a fair amount of testing in clinical settings,” Fischer says.

The results showed that fitted N95 masks blocked the greatest amount of droplets released by the person speaking, followed by surgical masks, then masks made with polypropylene.