In recent days, masks have become mandatory in all public spaces – indoors or outdoors – in Madrid, Greece, the Madeira Islands in Portugal and Hong Kong.
These moves apparently contradict the long-held idea that Covid-19 is more dangerous indoors. The UK government, among others, has used its first steps out of the lockdown to encourage people to meet outside; parks, beaches and natural sites around the world have been inundated with visitors throughout the pandemic.
But the reasoning behind the decisions is simpler than that: After months of mixed messages from health officials on face covers, governments are opting for blanket rules to help make mask wear a cultural norm.
What we now know about masks
The science behind airborne transmission of Covid-19 is growing, but experts still agree the risk is generally higher indoors.
Earlier this month, a group of 239 scientists wrote an open letter to the World Health Organization, calling for better recognition of the potential airborne transmission of the coronavirus. “A lot of people are cramming inside where it is poorly ventilated – that’s what is causing the pandemic,” a co-organizer of the letter and an environmental health professor told CNN.
But the outdoors is not free from Covid, and universal mask-wearing mandates have the potential to reduce the spread in many types of environments.
Researchers reported on Monday that communities that have mandated the use of face masks in public have seen a continued decline in the spread of the coronavirus, but it is taking time.
After the mandates were in place for about three weeks, the daily growth rate slowed by about 2% on average, researchers in the journal Health Affairs reported.
Their estimates suggest that these percentage declines could add up. They calculate that between 230,000 and 450,000 cases of Covid-19 could have been prevented by May 22 thanks to masked warrants.
Other scientists agree that there may be a significant risk of transmission outdoors.
“There is open air, so generally the risk is slightly lower, but it also spreads outdoors,” said Abrar Chughtai, an epidemiologist at the University of New South Wales. “Anytime you are unable to maintain social distancing, you should wear a mask. ”
“The risk is very low in an environment like a park or a large open space where there are not many people,” added Richard Stutt of the University of Cambridge in England, who modeled the impact of the port. mask to brake Covid-19 transmission.
“But if you’re walking down a busy shopping street, there’s a pretty big potential for spread there – and it would be very difficult to define exactly what constitutes high risk outdoor space versus low risk outdoor space. .
“There is further complication that if people constantly take off their mask and put it back on, they run the risk of contaminating their hands and passing it on to other people,” he noted.
This scientific knowledge is one of the factors leading to tighter mask mandates, which are also starting to appear in countries like the UK.
But there is also a sociological element at play, and it is simple: the mask rules work and therefore governments go further than they would have expected.
“There were a few countries that were holding out, thinking the public would revolt (to hide orders), but the public just don’t want to be in quarantine anymore,” Mills said. “Governments will be somewhat encouraged to expand their policies if they think these measures are working. ”
Many researchers are surprised at their effectiveness. In April, an extremely low proportion of Britons wore masks – just 19%, according to a Kings College study released on Thursday. But 70% of Britons now say they have worn one in the past few weeks, according to the same study.
“People became convinced very quickly that they were helping,” Bobby Duffy, director of the King’s Policy Institute and head of the study, told CNN. “There is a very, very high level of belief in their effectiveness, which in itself is quite remarkable given how quickly the advice has changed. ”
This change is particularly noticeable in a country where the government’s attempts to ease restrictions have been criticized as vague and confused. A University College London study last week found that only 45% of Britons believe they understand current government rules.
It was the same elsewhere in Europe; Hard-hit places like Italy and Spain saw mask use become a cultural norm almost immediately, and studies indicate that even in the United States – where a cultural war has erupted over the use of face masks – adhesion is generally very high.
“You can introduce these rules and people will follow them,” Duffy said. “It’s amazing how quickly people get used to things. You can also see it in the lockdown measurements; there was incredible support to go into lockdown, even when a few weeks (before) it would have seemed unthinkable. “
Are the lessons finally learned?
The benefits of expanded mandates are countless, but most significant is that they allow governments to harden their message by establishing a hard but simple rule: if you are in public, you must wear a mask.
“A general rule is a lot easier to stick to and apply,” Stutt said.
But many experts are upset that it has taken so long to get here – and implore other countries to do the same and make their mask laws black and white.
Mills said she was “really surprised and shocked” by conflicting guidelines from the World Health Organization and many governments, which said at the start of the pandemic that the use of masks was not necessary for curb the spread.
WHO Director-General Tedros Adhanom Ghebreyesus said last month the organization shifted gears and encouraged mask use after several weeks as the evidence evolved. “Our updated guidelines contain new information on the makeup of sheet masks, based on academic research requested by the WHO,” Tedros said last month.
“It was indeed very frustrating as a scientist, (because) there have been a lot of material studies that show that these good quality masks can really stop filtration,” Mills said.
In contrast, a number of Asian countries – many of which experienced the worst SARS outbreaks – were quick to encourage citizens to wear masks.
“Think about Japan: they were really effective and clear, they had the three Cs,” Mills said, referring to a government slogan ordering masks in closed spaces, crowded places and places of close contact.
“They keep repeating it and repeating it, and they had about 1,000 deaths out of a population of 126 million,” she added, noting that Japan’s relative success depended on several other factors.
“It’s not that simple, but places that wore masks from the start had significantly lower death rates,” Stutt added.
The adoption of stop-start in much of the West contrasted sharply with these countries. But now that governments feel confident enough to set tougher rules, experts may consider mask-wearing soon to become normal in all public places.
“A strong message from governments and organizations like the WHO has a significant effect on people, and makes wearing a mask much more socially acceptable and increasing adoption rates,” Stutt said.
“This compulsory use of masks is not going to lead to a huge rebellion from the majority of the population,” Duffy added, citing his research which has shown rapid adoption in the UK.
“There will be fractions that will oppose it very strongly – it will get a little bigger and louder, and our attention will be drawn to those people,” he said. “But the reality will be that the majority of the population will adapt and accept it. “
Naomi Thomas of CNN Health contributed to this report.