Coronavirus: Idea that face coverings lead to false sense of security is wrong and damaging, say Cambridge researchers
The idea that face coverings might lead to a false sense of security among their wearers - as once suggested by the World Health Organization (WHO) - is wrong and a threat to public health, researchers say.
Scientists at the University of Cambridge and King’s College London suggest it is unlikely that people wearing them will forego other vital important behaviour, such as good hand hygiene.
Instead, they believe it is the very idea of such ‘risk compensation’ - rather than the reality - that is the greater risk to public health, because it might discourage policy-makers from implementing effective measures, such as enforcing the wearing of face coverings.
There were warnings from WHO, early in the Covid-19 pandemic, that face coverings might “create a false sense of security that can lead to neglecting other essential measures such as hand hygiene practices”.
The UK government, in line with the WHO position, did not initially implement a policy that made face coverings mandatory in shops.
But in June, both the WHO and UK government changed their position, amid the growing weight of evidence that masks could play an important role in preventing the spread of infection, along with measures such as physical distancing and hand-washing.
Now, face coverings are required in many indoor venues in the UK, including shops, hospitals, cinemas and places of worship and on public transport.
Worldwide, wearing face coverings, particularly in shared indoor spaces, is mandated or recommended in more than 160 countries to prevent the spread of the virus.
A team led by Professor Dame Theresa Marteau, at the Behaviour and Health Research Unit at the University of Cambridge, examined the evidence for risk compensation.
The idea behind it is that people adjust their behaviour to maintain a target level of risk with which they are comfortable.
For example, a person may opt to run or work-out for longer to offset an indulgent meal, for example, or a cyclist may choose to wear a helmet to cycle at speed.
Evidence for risk compensation at a population level is less clear.
One commonly-cited claim is the idea that the introduction of HIV pre-exposure prophylaxis (PrEP) and HPV vaccination leads to an increase in unprotected sex.
But the most recent systematic reviews – which examine all available evidence on a topic – do not justify the concern of risk compensation. In fact, those who received the HPV vaccination were less likely to engage in unprotected sexual behaviour, as measured by rates of sexually transmitted infection.
There have been at least 22 systematic reviews on the effect of wearing a mask on transmission of respiratory virus infections.
Among them are six experimental studies, involving a total of more than 2,000 households, conducted in community settings that also measured hand hygiene.
None of these studies was designed to assess risk compensation or examined social distancing, but the results suggest that wearing masks does not reduce the frequency of hand washing or hand sanitising.
Two of the studies showed self-reported rates of hand washing were higher in groups allocated to wearing masks.
Meanwhile, there were three observational studies that showed people tended to move away from those wearing a mask. This suggests face coverings do not adversely affect physical distancing by those surrounding the wearer.
The authors of the latest paper note, however, that none of these studies has been peer-reviewed so should be treated with some compensation.
“The concept of risk compensation, rather than risk compensation itself, seems the greater threat to public health through delaying potentially effective interventions that can help prevent the spread of disease,” said Professor Marteau.
Co-author Dr James Rubin, from the Department of Psychological Medicine at King’s College London, said: “Many public health bodies are coming to the conclusion that wearing a face covering might help reduce the spread of SARS-CoV-2, and the limited evidence available suggests their use doesn’t have a negative effect on hand hygiene.
The researchers, who are supported by the National Institute for Health Research, argue the idea of risk compensation in relation to face coverings needs to be laid to rest.
Echoing Professor Barry Pless, from McGill University, Montreal, Canada, who once described it as “a dead horse that no longer needs to be beaten”, the authors say: “This dead horse now needs burying to try to prevent the continued threat it poses to public health”.
The Cambridge Independent has previously reported how University of Cambridge research showed that population-wide wearing of face coverings, worn correctly and in tandem with other measures, could play a crucial role in keeping the transmission rate down and preventing further waves of Covid-19.