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Facemasks are increasingly being used by the public in reaction to the current coronavirus outbreak.
Dr Ben Killingley, Consultant in Acute Medicine (Clinical Lead) and Infectious Diseases, University College London Hospital, said:
“Although images we see from virus affected areas always seem to show the general public wearing face masks, there is very little evidence that wearing such masks protects the wearer from infection. For example studies have shown that wearing of masks by individuals in a household that contains a influenza infected person does not confer significant protection. Furthermore, by the time household contacts are aware that someone in the household is infected, transmission could have occurred already.
“Furthermore, wearing masks can give a false sense of reassurance and might lead to other infection control practices being ignored, eg hand hygiene
“Specific respirator masks (in addition to other personal protective equipment) are worn by healthcare workers when looking after sick people but this situation is very different from the general public wearing surgical face masks, particularly when outside and when not in close contact with symptomatic individuals.
“There is some evidence to suggest that it useful for symptomatic individuals to wear a mask in an attempt to contain respiratory secretions.”
Prof William Keevil, Professor of Environmental Healthcare, University of Southampton, said:
“The public should not be alarmed at this time about the increasing numbers of COVID-19 in Asia and now Europe, and should continue good hygiene practice. Do not over rely on using standard masks regularly used by the general public which are surgical masks used in hospitals for short periods by trained professionals, changed frequently and properly disposed of. They are usually loose fitting, use poor filtration fabrics and give little protection to the wearer other than to restrict touching the nose and mouth without protecting the eyes. If you must, then use a close fitting N95-rated (FFP2) mask which offers good, although not complete, protection against infectious aerosols e.g. from coughs and has been shown to work well with flu virus. Higher standard N99-rated (FFP3) masks offer even better protection but some find them difficult to breathe through. Some masks have a valve in the front to help prevent moisture in exhaled breath condensing on the inside, making the mask wet and more libel to virus penetration. Guidance from many countries, including the UK, is that they are unnecessary at this time and the public should rely on washing hands regularly.
“Our published human coronavirus work showed these viruses can survive 3-4 days on common touch surfaces such as plastics, ceramics, glass and stainless steel (so called inanimate “fomites” such as door handles, chair arms, work tops, stair rails etc) , making hand transmission to eyes, nose and mouth a potential risk. WHO and CDC Atlanta also agree with this assessment of potential contagion and do not recommend that the general public wear masks. Therefore, wash hands regularly, clean work surfaces, door handles etc, try to avoid touching the eyes, nose and mouth. The PHE advice states that if you have travelled to category 1 Countries*, even if you don’t have symptoms, you should self-isolate and call 111. If you’ve travelled from Category 2 countries* but do not have symptoms, nothing needs to be done but if you do develop symptoms, you should self-isolate and call 111. They will then advise you on what to do but it’s important that if you are in self-isolation you should not go on public transport.”
Dr Stephen Griffin, Associate Professor Section of Infection & Immunity, University of Leeds, said:
“Standard facemasks provide relatively little protection from respiratory aerosols – they can stop larger droplets and some studies have estimated an approx. 5-fold protection versus no barrier alone. Also, once they are worn for a time, they become moistened and protection diminishes further. Exhaled droplets also reduce in size quickly by evaporation, and of course virus particles are far smaller than the fibre mesh in these sorts of masks.
“However, wearing a mask can reduce the propensity for people to touch their faces, which happens many more times a day than we all realise and is a major source of infection without proper hand hygiene. They are also useful for people that are themselves symptomatic in stopping coughs and sneezes, primarily by encouraging good “etiquette”, i.e. catch it, bin it, kill it…
“There are higher specification masks that contain filters and, when properly fitted and sealed, provide significantly better protection. However, these aren’t as easy to come by and are obviously more expensive.”
All our previous output on this subject can be seen at this weblink:
www.sciencemediacentre.org/tag/covid-19
The SMC also produced a Factsheet on COVID-19 which is available here:
www.sciencemediacentre.org/smc-novel-coronavirus-factsheet/
Declared interests
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