The widespread use of face masks in Britain could keep the reproduction rate below one and stop a second wave of coronavirus, a study suggests.
Modelling by the universities of Cambridge and Greenwich found if half of Brits wore masks it would prevent the crisis from spiralling back out of control.
The researchers said mask-wearing by everyone was twice as effective at reducing R compared to only asking symptomatic people to use them.
But they warned current social distancing and lockdown measures were not suffice to stifle the spread of Covid-19.
Lead author Dr Richard Stutt, from Cambridge University, said: ‘Our analyses support the immediate and universal adoption of face masks by the public.’
The UK’s R rate is thought to be between 0.7 and 0.9 — but some experts estimate it has crept above 1 in the North West and South West of England.
The R represents the average number of people an infected patient passes the virus to and keeping it below 1 is crucial to prevent a second surge of the virus.
Face coverings were only made mandatory in Britain when using public transport last week, with the rules coming into place on June 15.
The UK Government is not convinced they are helpful in other scenarios and believe they may do more harm than good by giving people the false confidence to take unnecessary risks.
Different face coverings have varying levels of protection – for example, a scarf is much less effective than a medical-grade surgical mask. But the modelling by Cambridge and Greenwich shows the R rate would plummet below zero even with a covering that is just 75 per cent effective and only worn by half of Britons. The research claims it is much more effective to have everyone wearing masks rather than just symptomatic people
The widespread use of face masks in Britain could keep the reproduction rate below one and stop a second wave of coronavirus, a study suggests
There is also a concern that people who wear masks touch their face more and increase the risk of viral particles entering their airways.
But the latest model took into consideration the fact people might fidget with the masks, wear them wrong and take unnecessary risks.
The researchers estimated the transmission rate based on levels of compliance from the public.
If 50 per cent or more of the population wore them then the R will remain below one as long as social distancing stayed in place and lockdown was eased very gradually.
If every single Briton wore masks in public then the scientists estimate it could keep R stable without any draconian curbs.
But the researchers admit it would be highly unlikely that everyone would adhere to the rules.
Lead author Dr Richard Stutt, part of a team that usually models the spread of crop diseases at Cambridge, said the finding suggested mask-wearing needed to be ‘immediately’ enforced in the UK.
He added: ‘If widespread face mask use by the public is combined with physical distancing and some lockdown, it may offer an acceptable way of managing the pandemic and re-opening economic activity long before there is a working vaccine.’
The researchers found that even homemade masks with limited effectiveness would dramatically reduce transmission rates if worn by enough people.
Previous studies have suggested that homemade face coverings have up to 90 per cent of the same protective effect as surgical masks.
The latest study claims that an entire population wearing masks of just 75 per cent effectiveness could keep the R below one even if lockdown is eased.
Professor John Colvin, co-author from the University of Greenwich, said: ‘There is a common perception that wearing a face mask means you consider others a danger.
‘In fact, by wearing a mask you are primarily protecting others from yourself. Cultural and even political issues may stop people wearing face masks, so the message needs to be clear, ‘My mask protects you, your mask protects me’.
‘In the UK, the approach to face masks should go further than just public transport. The most effective way to restart daily life is to encourage everyone to wear some kind of mask whenever they are in public.’
Officials last week released a Blue Peter-style guide on how to make one from an old T-shirt
The study was published in the journal Proceedings of the Royal Society A.
Reacting to the findings, Professor Keith Neal, emeritus professor of the epidemiology of infectious diseases at the University of Nottingham, said: ‘Clearly there is some face validity to the suggestions that the more people who wear masks the more impact this might have on the spread of COVID-19.
‘But this is highly dependent on the effectiveness of the masks the public will use. The problem we have is there is no hard data on the effectiveness of the masks the public will use.
‘Also, the model itself has six parameters (particularly about infectiousness of droplets and spread of different types of infectious material) which were arbitrarily defined.
‘The findings of the model, like all other models, is highly dependent on the assumptions made on these parameters. If any of the assumptions are significantly wrong this will affect the conclusion of the study.’
Dr Ellen Brooks Pollock, senior lecturer in public health and infectious disease modelling t the University of Bristol, said there were a few discrepancies in the modelling.
She said: ‘While face masks might be able to reduce transmission in some settings, such as shops or public transport, it is unlikely that face masks will prevent transmission for close and sustained social contacts, such as at home, because it would be impractical to wear a facemask effectively for 24 hours a day.
‘In this paper, the authors optimistically assume that 100 per cent of transmission events could be prevented with face masks. In reality, 15 per cent of contacts and a third of all contact hours occur in the home, and therefore these transmission events would not be prevented with face mask use.
‘Therefore, the likely impact of face masks is much smaller than is predicted in this modelling study.’
Research on how well various types of masks and face coverings varies but, recently, and in light of the pandemic of COVID-19, experts are increasingly leaning toward the notion that something is better than nothing.
A University of Oxford study published on March 30 concluded that surgical masks are just as effective at preventing respiratory infections as N95 masks for doctors, nurses and other health care workers.
It’s too early for there to be reliable data on how well they prevent infection with COVID-19, but the study found the thinner, cheaper masks do work in flu outbreaks.
The difference between surgical or face masks and N95 masks lies in the size of particles that can – and more importantly, can’t – get though the materials.
N95 respirators are made of thick, tightly woven and molded material that fits tightly over the face and can stop 95 percent of all airborne particles, while surgical masks are thinner, fit more loosely, and more porous.
This makes surgical masks much more comfortable to breathe and work in, but less effective at stopping small particles from entering your mouth and nose.