Masks against COVID-19: research supports universal adoption

Spatial distancing and personal face mask use could help enable a safer lifting of coronavirus (COVID-19)-induced restrictions around the world, according to a comment published in The Lancet by Professor Raina MacIntyre from UNSW Sydney’s Kirby Institute. The comment addresses a World Health Organizaton (WHO) commissioned systematic review by Chu et al. which analysed all available studies on SARS, MERS CoV and SARS CoV-2 (the virus that causes COVID-19), in order to understand more about the true impact of physical distancing, face masks and eye protection for the prevention of COVID-19.

The research addressed in the commentary showed an 82% reduction in risk with one metre of physical distance between people in healthcare and community settings, with every additional metre of separation doubling the relative protection. “This important evidence supports the current Australian recommendation for maintaining a physical distance of 1.5 metres from others. As we move to lift restrictions, this evidence suggests safe resumption of business and social activities can be enabled by continued physical distancing,” Professor MacIntyre, who heads up the Kirby Institute’s Biosecurity Program, said.

Masks

“The research in The Lancet shows that risk can be further reduced by the use of face masks,” Professor MacIntyre added. The research reported that masks and respirators reduced the risk of infection by 85%, and face masks were equally effective when used in the community and in healthcare settings, even well-designed 12-layer cloth masks. “When you are out and about, you cannot tell who is infected and who is not,” Professor MacIntyre said. “You yourself may be infected and not know it. Especially with the growing evidence of pre-symptomatic and asymptomatic transmission, universal face mask use is an important way to reduce the spread of infection.”

This is particularly important in regions with high incidence of COVID-19. However, in countries with low prevalence, like Australia, where there has been considerable success in containing the virus, face mask use is not mandated and not yet widely recommended, except for on public transport. It may be a consideration for the future, with a return to crowded public settings and the feasibility of large public gatherings around Christmas and New Year. The research was commissioned by WHO, involved more than 40 international researchers from nine countries and was conducted with The Cochrane Canada and McMaster GRADE Centre, using leading analytical methods. The review had some limitations, in that it relied on observational studies, as opposed to the gold standard randomised control trials (which would be unethical to conduct on SARS-CoV-2 for this type of research).

Conclusion

“There is no foolproof method for reducing risk to zero, but this is the best evidence we have to date on these specific coronaviruses,” Professor MacIntyre said. “The most important message from this study is that no intervention on its own is 100% effective — but with a combination of distancing, mask use and other inventions, we can hold COVID-19 at bay until an effective vaccine is developed.”

The full comment, titled ‘Physical distancing, face masks, and eye protection for prevention of COVID-19’, was published open access in The Lancet.

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