Masks and visors do help limit spread of Covid-19

According to 10 studies included in the meta-analysis, the risk of infection or transmission of viruses is 3% when participants wear masks, as opposed to 17% when they do not. (Rawpixel pic)

OTTAWA: According to a new study published in The Lancet, masks, visors and other measures used to protect against Covid-19 effectively limit transmission of the virus.

Face masks, visors, and maintaining a distance of one or two metres between individuals… A meta-analysis commissioned by the World Health Organisation (WHO) and led by a team of researchers from McMaster University and St Joseph’s Healthcare Hamilton (Canada) has evaluated the effectiveness of these methods in controlling the Covid-19 epidemic.

The results were published this week in the prestigious medical journal The Lancet.

The study reviewed data on three coronaviruses (SARS 2002, MER and Covid-19) from 172 observational studies conducted in 16 countries and six continents, which were carried out until early May 2020.

No randomised controlled trial data was available on the subject, however, 44 comparative studies involving 25,697 patients, which were deemed to be relevant, were also selected by the researchers.

Ten of these studies involving 2,647 participants showed that the risk of infection or transmission of viruses was 3% when participants wore masks, as opposed to 17% when they did not.

A reduction of the recommended physical distance from two meters to one meter also doubled the risk of infection from Covid-19, the study found.

The authors of the publication point out that more research is needed on the different strategies for personal protective equipment. They also insist on the urgent need for randomised trials, notably with regard to the wearing of masks.

“However, although distancing, face masks, and eye protection were each highly protective, none made individuals totally impervious from infection and so, basic measures such as hand hygiene are also essential to curtail the current Covid-19 pandemic and future waves,” warns Derek Chu, a clinician scientist at McMaster University and a co-author of the study.