Medical workers should have top priority when it comes to wearing protective face masks. But if that can be ensured, it’s also beneficial for the general population to wear masks.

Improvised and homemade cloth masks can be a way to satisfy both needs.

The guidance on wearing face masks has been one of the most bizarre turns of events in the current outbreak. Initially, all guidance (except for some countries in Asia — i.e. South Korea, China) was against using face masks. The evidence was too inconclusive, most experts said. The US Surgeon General even specifically asked people to stop buying face masks otherwise there might not be enough for medical workers.

Not long after that, however, the guidance took a 180 turn, and symbolically, the Surgeon General even made a video showing people how to make an improvised face mask using only an old T-shirt and a rubber band.

But we never really got an answer: were we not supposed to wear face masks because they’re not effective, or because we could cause a shortage?

We can’t really be sure what the case was, but as far as the evidence is concerned, it’s becoming clearer and clearer that face masks can provide protection. It’s not perfect, it’s only partial, but it’s significant nonetheless, and it can go a long way towards limiting disease transmission.

We’ve covered quite a few studies, both recent, and a bit older, and the conclusion is always the same: wearing face masks can prevent the transmission of respiratory diseases, and in the case of the novel coronavirus, they can be particularly useful.

A new review, carried by US-based researchers adds even more weight to that theory. The review of existing literature finds that the more people wear masks, the more we can prevent the spread of disease.

“The preponderance of evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at stopping spread of the virus when compliance is high,” the review concludes. The researchers did not carry any new experiments, only a review of existing published literature.

The recommendation of the researchers, to enjoy the protection of face masks but not to cause shortages, is to use cloth masks.

The good thing about cloth masks — for all their imperfect protection — is that they come at a very low cost. Essentially, a decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low.

“We recommend the adoption of public cloth mask-wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation,” the study concludes.