Few changes to our lives brought about by the coronavirus pandemic have been more obvious than the increased use of face masks.
While wearing a face covering was already commonplace in many Asian countries, partly due to the Sars outbreak of the early 2000s, in other parts of the world they were rarely seen.
Queen Mary University of London
Now, even in contexts where mask wearing is not mandated, their use is seen as normal and barely attracts a second glance.
But for how much longer will face coverings be used routinely? Here we consider this question in relation to schools, which have been subject to fierce debate over whether mask wearing should continue.
Do face coverings prevent the spread of the coronavirus in schools?
Two recent studies from the US indicate that masks may indeed be effective at reducing transmission of the coronavirus among schoolchildren.
One, looking at cases from August to October last year, found a 23 per cent lower incidence of Covid-19 in school districts of Arkansas, where masks were required.
The other piece of research, analysing data from nine US states, found 72 per cent less transmission of the coronavirus in schools were mask-wearing was compulsory.
A scientist not connected to the studies, Prof Paul Hunter, professor in medicine at the University of East Anglia in the UK, struck a cautionary tone regarding the findings.
They were observational studies, he noted, rather than randomised controlled trials.
As a result, he said, they could be subject to bias, although he added that research has tended to indicate that wearing masks does reduce the risk of coronavirus spread in schools, but does not stop it.
“By and large where mask wearing was optional, you get increased rates of secondary transmission,” Prof Hunter said.
For how much longer will masks be required?
Some countries, such as England, have already lifted the requirement for pupils to wear face coverings, while in the US, some states that imposed mask mandates, like California, Oregon and Washington, have dropped them.
Rules requiring masks to be worn in schools remain in place in many areas. In Dubai, for example, the Knowledge and Human Development Authority lifted a requirement early this month for masks to be worn outside in private schools, universities and early childhood centres – but said they were still needed indoors.
Elsewhere, such as in France, requirements have been dropped and reimposed. Regulations can vary according to the age of pupils.
Prof John Oxford, emeritus professor of virology at Queen Mary University of London and co-author of Human Virology, said it had been “surprising” how effective masks had proved to be at preventing the spread of the coronavirus.
“They’re cheap, they’re easily made,” he said. “I would encourage groups who want to continue using them to continue using them. It’s not the end of the world putting on a paper mask.”
In the tropics, Prof Oxford said the transmission of respiratory infections was year-round, but further from the equator, he noted that the spread typically happened most in winter.
As Covid-19 becomes an endemic infection with case numbers peaking in the cooler months, he said mask-wearing in schools should probably become seasonal too. So in the summer masks may not be needed, but in winter it may become necessary to wear them again in schools, potentially indefinitely.
“It’s going to turn into a seasonal virus,” he said. “When the respiratory [infection] season begins, you get prepared to put your mask on.”
Is there an argument for ending mask-wearing in schools entirely?
While saying that masks have been shown to reduce transmission in schools, Prof Hunter said there may be little benefit to many children in continuing to use them.
In countries such as the UK, where infection rates have been high, most children have already had a Covid-19 infection and some will have had two, he said. In such children, because their immune system gives them good protection thanks to natural infection (as well as, potentially, vaccination) “there’s not a huge amount of benefit” in continuing to wear a mask.
“I think in England it’s right [to end mask-wearing requirements] because most kids, the vast majority, have had at least one infection if not more infections,” he said.
“That wouldn’t necessarily apply in New Zealand [where there have been far fewer infections]. It depends on the context.”
Prof Hunter warned that continuing with mask-wearing could have a downside.
He said if people were exposed to the coronavirus periodically, their immune defences were likely to remain strong and, each time they were infected, the chances of serious illness were lower.
Efforts to prevent spread, such as mask wearing, may lead to longer gaps between when individuals are exposed to the coronavirus. As a result, when a person did become infected, Prof Hunter said they may be more likely to fall seriously ill.
“These sorts of measures could potentially make things worse by increasing the gaps between infections,” he said.
