Widespread facemask use could shrink the ‘R’ number and prevent a second COVID-19 wave – study


11-06-2020
  Wear a mask  Credit: Mike Licht

Even basic homemade masks significantly reduce transmission at a population level, according to latest modelling. Researchers call for information campaigns that encourage the making and wearing of facemasks.

Population-wide use of facemasks keeps the coronavirus ‘reproduction number’ under 1.0, and prevents further waves of the virus when combined with lockdowns, a modelling study led by the University of Cambridge suggests.

The research suggests that lockdowns alone will not stop the resurgence of SARS-CoV-2, and that even homemade masks with limited effectiveness can dramatically reduce transmission rates if worn by enough people, regardless of whether they show symptoms. 

The researchers call for information campaigns across wealthy and developing nations alike that appeal to our altruistic side: 'my facemask protects you, your facemask protects me'. The findings are published in the Proceedings of the Royal Society A.

“Our analyses support the immediate and universal adoption of facemasks by the public,” said lead author Dr Richard Stutt, part of a team that usually models the spread of crop diseases at Cambridge’s Department of Plant Sciences.

“If widespread facemask use by the public is combined with physical distancing and some lockdown, it may offer an acceptable way of managing the pandemic and reopening economic activity long before there is a working vaccine.”

Dr Renata Retkute, coauthor and Cambridge team member, said: “The UK government can help by issuing clear instructions on how to make and safely use homemade masks.”

“We have little to lose from the widespread adoption of facemasks, but the gains could be significant.”

The new coronavirus is transmitted through airborne droplets loaded with SARS-CoV-2 particles that get exhaled by infectious people, particularly when talking, coughing or sneezing.

For the latest study, Cambridge researchers worked to link the dynamics of spread between individuals with population-level models, to assess different scenarios of facemask adoption combined with periods of lockdown.

The modelling included stages of infection and transmission via surfaces as well as air. Researchers also considered negative aspects of mask use, such as increased face touching.

The reproduction or ‘R’ number – the number of people an infected individual passes the virus onto – needs to stay below 1.0 for the pandemic to slow.

The study found that if people wear masks whenever they are in public it is twice as effective at reducing ‘R’ than if masks are only worn after symptoms appear.

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Image:  Wear a mask

Credit: Mike Licht

Reproduced courtesy of the University of Cambridge

 

The University of Cambridge is acknowledged as one of the world's leading higher education and research institutions. The University was instrumental in the formation of the Cambridge Network and its Vice- Chancellor, Professor Stephen Toope, is also the President of the Cambridge Network.

University of Cambridge (cam.ac.uk)