Coronavirus: Wearing face masks could lower death rate 5%

Everybody wearing face coverings in public could reduce a country’s Covid-19 death rate by five per cent, according to a study.

And if medical masks are given to the elderly and people currently sick with Covid-19, the effect doubles.

Applying this to the UK’s death toll of 41,329 suggests the strategy could have saved 10 per cent of the victims’ lives – a total of more than 4,000 individuals.

However, medical masks have not been widely available because of immense global demand and members of the public were advised against buying them up to make sure medical workers didn’t run out.

And wearing face coverings of any kind was not encouraged until June in the UK, months after the peak of the pandemic.

Mask-wearing of any kind among the public has been a contentious issue throughout the pandemic because officials said they would not advise it until there was clear evidence they worked – and proof that they do is still uncertain.

Face coverings worn by the public can reduce the Covid-19 death rate by five per cent, according to a study. Pictured: UK Prime Minister Boris Johnson in Belfast, August 13

Face coverings worn by the public can reduce the Covid-19 death rate by five per cent, according to a study. But if medical masks are given to the elderly and people currently sick with Covid-19, the effect doubles. This can be seen in the dark orange column (10 per cent reduced deaths)

The graphs show different scenarios of medical face mask-wearing in the population. All graphs show that the biggest reductions in deaths are seen when 50 per cent of the elderly and 50 per cent of infected people wear masks (the light blue line). Graph G shows the biggest reduction because this is when the masks are offering 75 per cent protection and 75 per cent containment. In comparison, C shows the smallest reduction

The research, published today in the journal Nature Communications, was led by Dr Colin Worby of the Broad Institute of MIT and Harvard.

He and Hsiao-Han Chang, of the National Tsing Hua University in Taiwan, used mathematical modelling to examine the impact of face mask use among the general population during a coronavirus outbreak.

They primarily looked at medical-grade masks – referred to as ‘face masks’ – as opposed to ‘face coverings’, which can be made of cloth.

THE TRUTH ABOUT FACE MASKS: WHAT STUDIES HAVE SHOWN

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 their 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.

Droplets of saliva and mucous from coughs and sneezes are very small, and viral particles themselves are particularly tiny – in fact, they’re about 20-times smaller than bacteria.

For this reason, a JAMA study published this month still contended that people without symptoms should not wear surgical masks, because there is not proof the gear will protect them from infection – although they may keep people who are coughing and sneezing from infecting others.

But the Oxford analysis of past studies- which has not yet been peer reviewed – found that surgical masks were worth wearing and didn’t provide statistically less protection than N95 for health care workers around flu patients.

However, any face mask is only as good as other health and hygiene practices. Experts universally agree that there’s simply no replacement for thorough, frequent hand-washing for preventing disease transmission.

Some think the masks may also help to ‘train’ people not to touch their faces, while others argue that the unfamiliar garment will just make people do it more, actually raising infection risks.

So what about cloth coverings? Although good quality evidence is lacking, some data suggest that cloth masks may be only marginally (15 per cent) less effective than surgical masks in blocking emission of particles, said Babak Javid, principal investigator at Cambridge University Hospitals wrote in the BMJ on April 9.

He pointed to a study led by Public Health England in 2013 which found wearing some kind of material over the face was fivefold more effective than not wearing masks for preventing a flu pandemic.

The study suggested that a homemade mask ‘should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection’.

The authors simulated outbreaks in which availability and effectiveness of medical face masks varied and analysed how it impacted the the total numbers of infections and deaths.

Mask effectiveness refers to how well the mask ‘protects’ a person from other infectious people, and how well it ‘contains’ the wearers viral particles. The effectiveness ranged from 25 to 75 per cent.

And availability, modelled with a complex calculation, refers to how many masks are being produced and the demand for them as cases increase.

Across the models used, deaths and infections were lower when masks were increasingly available and effective.

Even there were only face masks to supply 10 per cent of the population, with just 25 per cent effectiveness, it could result in five per cent fewer deaths, the model showed.

The authors considered four strategies for doling out face masks to the public when there is a limited supply.

These were random distribution, prioritised distribution to the elderly, distribution to diagnosed cases, and distribution to both the elderly and diagnosed.

In all the models, it was assumed that healthcare workers had enough face masks and there were left over supplies.

The authors found the best combination was prioritising the elderly and infectious cases. This reduced deaths more than random mask-wearing in the public.

Giving masks only to people who were diagnosed with Covid-19 was relatively pointless, the study said, because so many people – estimated 30 per cent in this model – are not diagnosed because they do not show symptoms.

But there was still a dramatic decline in deaths if only the elderly wore medical masks, the study found.

Data and studies have repeatedly shown that the risk of dying of Covid-19 increases drastically with age, and the vast majority of victims in the UK have been middle-aged or elderly.

Then the team modelled what would happen if the general public adopted face coverings – such as a cloth or scarf – on top of the different face-mask scenarios.

The medical face masks were assumed to be three times more protective than face coverings across all scenarios.

In all scenarios the combination of face coverings and providing the elderly and infected with medical masks reduced deaths by the maximum amount.

The researchers found that ‘face coverings provided a considerable reduction in total deaths’.

Just face coverings alone reduced deaths by three to five per cent.

This was the same as when the elderly and symptomatic wear medical face masks when there were limited supplies for 10 per cent of the population. Therefore, deaths could be reduced by a total of ten per cent when the measures are put together.

‘For a population with a universal recommendation for face covering in public (e.g. the United States post-April 2020), a reduction of three to five per cent in deaths may be expected’, the team wrote.

‘An additional targeted distribution of surgical masks to the elderly and symptomatic can at least double this effect.’

The authors concluded that face mask use is an important component of public health measures to limit the ongoing spread of SARS-CoV-2.

They wrote in their paper: ‘With no available vaccine and limited therapeutic options, face mask use is an important component of public health measures to limit the ongoing spread of Covid-19.’

However, further studies are required to obtain improved estimates for mask effectiveness among the public during the COVID-19 pandemic.

The use of surgical masks as an infection control measure is common in East and South East Asia, and countries there were quick to tell citizens to use them to curb the spread of Covid-19.

But Western countries have been slower to encourage any adoption of masks, mostly because policy makers say there isn’t enough evidence to support them.

The Centre for Disease Control and Prevention did not recommended cloth face coverings until April, while the UK government waited until June.

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