If economies are to re-open without creating a second wave of COVID-19, we should not let our masks slip.
One of our concerns as governments around the world gradually ease their lockdowns is the potential for a second wave of the coronavirus.
We know that the path back to normality remains long and uncertain, but encouraging evidence is emerging that one relatively simple measure could help avert this second wave: wearing masks.
While we should be clear that the cotton masks likely to be worn by most of the population cannot eliminate the transmission of the virus, academics believe they have some efficacy in limiting how the virus is spread by people speaking, coughing, and sneezing.
This is absolutely critical as approximately half of infections come from pre-symptomatic individuals. The global containment strategy is to reduce the disease’s reproduction number below one to prevent it spreading exponentially, so anything that can make transmission less likely is valuable. Cotton masks may not keep the wearer entirely safe from contracting the virus – as medical masks can – but they can lower the chances of wearers infecting others.
On the question of how effective masks can be in this regard, a new academic paper reviews the literature. As illustrated in the slide below, masks that are 50% efficient in arresting the spread of the virus could – on their own – reduce the COVID-19 reproduction number to one if around 75% of people wore them.
Other studies we have reviewed similarly report a correlation between early mask adoption and containing the spread of the virus.
The paper mentioned above uses a 50% mask efficiency rate and a 50% adoption rate “as a conservative assessment”. The exact efficiency of a mask will be subject to many factors, but we can conclude that weaker masks will need higher adoption rates and vice versa.
So what do we know about the probable adoption rate for mask wearing? Survey data from YouGov reveal that face masks are already common in much of Asia, with 85-90% of respondents saying they wear them in public. Adoption is also rising to critical levels in the US, Germany, and France, where more than 60% of people say they use face masks. The outlier is the UK, where less than 20% of people said they wore face masks in public.
We need to check whether these survey responses are reflected by actual behaviour on the ground, but to improve adherence academics recommend that masks be made compulsory in public settings. The theory is that this should reduce the stigma and discrimination against those wearing them, given presumptions that masks imply illness or fear and that some employers have asked staff not to wear masks to avoid ‘scaring’ customers.
If mask-wearing did become mandatory, it could help limit the risk of out-of-control second waves of the virus; smaller outbreaks could still occur, of course, but would be easier to track and trace, particularly through new apps.
And if masks also made people more comfortable returning to their pre-pandemic lifestyles, we would expect economic advantages too. One of the risks we have identified regarding the re-opening of economies is that people may not want to resume their normal behaviour even when governments loosen restrictions for fear of the virus lurking.
Avoiding further tragedy is undoubtedly the best argument for wearing masks, but restoring public confidence will be important too.