Cambridge experts call for widespread face mask use in COVID-19 crisis
In a new editorial published in The BMJ, a trio of Cambridge University researchers suggest wearing of cloth masks should be adopted by everyone during the COVID-19 pandemic. The team argues the potential benefits of this behavior far outweigh any of the suggested downsides.
“We know that a lot of transmission of the coronavirus occurs before people show any symptoms,” explains Babak Javid, an infectious disease consultant from Cambridge Universities Hospitals NHS Trust. “Wearing masks is primarily to protect others, as well as offering some degree of protection to the wearer.”
The arguments for and against large-scale mask wearing have been hotly debated over the past weeks, with the US Centers for Disease Control and Prevention (CDC) notably changing its general advice last week, ultimately advocating for widespread cloth mask use.
There are three general arguments frequently presented against broad general use of face masks: there is no evidence they protect a person from contracting the virus, mass adoption takes valuable resources away from frontline healthcare workers, and they instill a false sense of security in the wearer, resulting in reduced adherence to other important hygiene measures.
The editorial does note prior research investigating real-world mask use in regards to influenza transmission found masks confer “no significant protection.” However, many of the arguments for mask wearing suggest the point of advocating broad mask use is about limiting transmission from those unaware they are infected, instead of acting as a protective measure for healthy subjects.
The team is clear in pointing out medical-grade face masks must be reserved for healthcare workers. But, how useful then are simple cloth face masks?
“Although good quality evidence is lacking, some data suggest that cloth masks may be only marginally (15%) less effective than surgical masks in blocking emission of particles, and fivefold more effective than not wearing masks,” the researchers write in the editorial. “Therefore, cloth masks are likely to be better than wearing no mask at all.”
So, if, at the very least, a cloth face mask may offer even a minimal reduction in virus particles being transmitted, why isn’t it an agreed general recommendation?
Because … the general public doesn’t seem to be able to understand how to use face masks safely and some experts, including the World Health Organization (WHO), suggest they can do more harm than good.
“The untrained public can be regularly seen on television continuously touching and readjusting the masks, contaminating their hands and risking contacting their eyes,” explains William Keevil, from the University of Southhampton, in reference to the recent WHO advice against widespread mask wearing. “Indeed, what is the point of wearing a mask if you also do not protect your eyes, a known route for virus entry, as healthcare professionals do by wearing goggles and/or a full face visor.”
Trish Greenhalgh, a primary health care specialist from the University of Oxford, says this argument tends to underestimate the ability of the general public to learn how to use face masks properly.
“… a key argument against them seems to be that the public can’t be trusted to follow instructions for how to fit and wear them properly, which is a bit patronizing in the current circumstances,” says Greenhalgh. “An argument in favor of masks is that people may well be highly motivated to learn the proper techniques for wearing their masks properly.”
The Cambridge team backs up this point in the editorial noting, while the "false sense of security" argument is not invalid, it really is a matter of educating the general public on how to correctly and safely use cloth masks.
“In practice, however, we don’t counsel against other non-pharmacological interventions with similar levels of evidence, just in case they instill a false sense of security,” the team writes in the editorial. “And, as with recent handwashing campaigns, mass education about the safe use and removal of masks would be possible. Importantly, if a mask is contaminated at removal, it has (by definition) already protected the wearer from contagious droplets.”
Nicholas Matheson, from the Cambridge Institute of Therapeutic Immunology and Infectious Disease, and one of the authors of the new editorial, also points out the broad psychological effect of widespread mask wearing. The simple sight of mass public mask wearing can serve as a valuable visible reminder of the pandemic.
“As we prepare to enter a ‘new normal’, wearing a mask in public may become the face of our unified action in the fight against this common threat, and reinforce the importance of social distancing measures,” concludes Matheson.
The new editorial was published in The BMJ.
Source: University of Cambridge