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The government have announced that from the 24th July face coverings will be mandatory in England’s shops to help limit the spread of COVID-19.
Dr Julian Tang, Associate Professor of Respiratory Sciences at the University of Leicester, said:
“I think this is a sensible decision. Masking will reduce further virus transmission along with social distancing and hopefully avoid another local lockdown.
“The evidence on face mask effectiveness is mostly lab-based but it is reasonably robust as a basis on which to form guidance. You cannot control how and when people wear their masks (over the mouth not the nose, taking it off for lunch, coffee breaks, etc., but if you are looking for just the potential effectiveness of the mask as a physical barrier when worn correctly, this is the best you can do.
“Studies have demonstrated that surgical masks can contain and therefore reduce the dissemination of droplets and aerosols produced by a sick wearer by up to 3-4-fold (i.e. ~67-75%) [Milton et al. 2013; Leung et al. 2020], to protect others. Surgical masks can also protect the wearer to some degree by reducing the exposure to incoming droplets and aerosols by up to 6-fold (i.e. ~83%), from others who are ill [HSE 2008; Makison Booth 2013].
“Home-made cloth masks (made out of tea cloths in this study) can reduce the exposure from incoming aerosols by up to 2-4 fold (i.e. ~50-75%) [van der Sande et al. 2008], though this will depend to some extent on how the mask is made, what it is made from, and the nature of the aerosols to which it is exposed.
“Finally, a comprehensive review of face shields (or visors) suggest a protection efficacy slightly higher than surgical masks initially, from immediate exposures, but which decreases over time as the finer aerosols produced start to be inhaled underneath the visor [Roberge 2016, https://pubmed.ncbi.nlm.nih.gov/26558413/]. Note that to optimise protection the face shield has to curve round the sides of the face to the ears, and to extend down long enough in front of the face, to reduce aerosol entry from the sides and underneath the shield as much as possible. Face shields/visors have the added advantage that they include eye protection, as well as being washable and reuseable, being less claustrophobic, and generally allowing mostly normal communication if worn instead of a face mask, though both can be worn in combination for added protection.
“Comparing their relative effectiveness of different measures such as face masks and social distancing is very difficult in different scenarios. So a better way to think about it is to treat all the measures as incremental – and one can act as a backup to another if the situation does not allow it, e.g. if social distancing is difficult, like on a train or bus, then wearing a mask gives you that added protection, similarly in a crowded shopping aisle where people just forget their social distancing – the mask offers an extra layer of protection.
“One of the main problem so far in this COVID-19 pandemic in Western countries is that there is too much attempt at defining things as black and white: e.g. masks don’t work, the virus is not airborne, asymptomatics don’t transmit, etc. It is more useful to think of such questions on a spectrum so measures can be out in place to cover this: – masking helps to support social distancing in reducing transmission indoors in potentially crowded areas, like shops and public transport.
“You can’t separate airborne/aerosols of virus from droplets when people are speaking, breathing, laughing (during coughing/sneezing, people naturally cover up or turn away), so open windows, enhance ventilation, wear masks when near other people – since we cannot be absolutely sure that asymptomatic infected people cannot transmit, then continue to test and isolate them – especially if they are to return to a care home
“Most of the world’s population is still susceptible to this virus, and we are still not sure how long any post-infection immunity will last, so if people can get used to all these precautions now, it will reduce the numbers of COVID-19 cases/deaths over a longer-term – these precautions will also work for reducing the transmission of other seasonal respiratory viruses, like influenza.”
References:
Milton DK, Fabian MP, Cowling BJ, Grantham ML, McDevitt JJ. Influenza virus aerosols in human exhaled breath: particle size, culturability, and effect of surgical masks. PLoS Pathog. 2013 Mar;9(3):e1003205. doi: 10.1371/journal.ppat.1003205.
Leung NHL, Chu DKW, Shiu EYC, Chan KH, McDevitt JJ, Hau BJP, Yen HL, Li Y, Ip DKM, Peiris JSM, Seto WH, Leung GM, Milton DK, Cowling BJ. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med. 2020 May;26(5):676-680. doi: 10.1038/s41591-020-0843-2.
Health and Safety Executive UK. RR619 Evaluating the protection afforded by surgical masks against influenza bioaerosols. 2008. ttps://www.hse.gov.uk/research/rrhtm/rr619.htm (Accessed 13 July 2020)
Makison Booth C, Clayton M, Crook B, Gawn JM. Effectiveness of surgical masks against influenza bioaerosols. J Hosp Infect. 2013 May;84(1):22-6. doi: 10.1016/j.jhin.2013.02.007.
van der Sande M, Teunis P, Sabel R. Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLoS One. 2008 Jul 9;3(7):e2618. doi: 10.1371/journal.pone.0002618.
Dr Shaun Fitzgerald, Royal Academy of Engineering Visiting Professor, University of Cambridge, said:
“There are different face coverings, but they all work to help reduce transmission. They are one of the mitigation measures which we have in our armoury to tackle this virus, and people should be using many of them to hit all of the transmission pathways. Adoption of face coverings indoors where there are multiple people, and especially in areas where 2m social distancing is hard, is very sensible.”
Dr Simon Clarke, Associate Professor of Cellular Microbiology at the University of Reading, said:
“The latest announcement by the Government on the mandatory wearing of masks in shops builds on recent reports by the Royal Society which, taken together, provide good new evidence for updating advice on face masks. In particular, the evidence around behavioural science and the adherence of mask wearing is particularly useful.
“As the recent SET-C report says, people need clear and consistent advice on reducing risks to themselves and others. The new law around wearing face coverings in shops is perhaps the most unambiguous way to make the behaviour change happen by criminalising non-adherence. We can however clearly see that there is a balancing of the scientific evidence with political will, as economic pressures butt up against ways of limiting the spread of Covid-19. I have said before, the most effective barrier to avoid catching Covid-19 is your front door, but as restrictions on movement and activities are coming to an end, the infection peak has reduced, and we have more evidence from around the world, it is time that the government refreshes its entire package of advice on reducing infections..
“Those recent reports have shown that it is possible to convince people to start wearing masks en masse, even in countries without a history of mask wearing. However, reducing infections requires a complete package of behavioural change, and facemask wearing should not be seen as an end in itself. Universal or more frequent facemask wearing, coupled with clear advice on how to use them properly, can be part of this package to prevent infections.”
Dr David Strain, Clinical Senior Lecturer, University of Exeter and also chair of the British Medical Association’s Medical Academic Staff Committee, said:
“We need masks to slow the spread and make life safer for the most vulnerable to go about essential activities. In the latest BMA survey, 86% of over 5000 doctors agreed that this should be mandated. England is one of last countries in Europe to mandate the use of face coverings to reduce the risk of the spread of coronavirus from asymptomatic carriers in order to facilitate the safer easing of lockdown. Even now, they wish to wait another 10 days before implementing the change.
“Yesterday more than 500 people tested positive for the virus, which the ONS figures suggest is only about 1/3rd of the true number of new cases in the UK. The remaining 2/3rds of the population with the virus are the “silent spreaders”, people who carry and can potentially spread the virus despite having no symptoms themselves. The mandatory use of face coverings will reduce the risk to the population at large from these individuals. There is clear evidence that a cloth face covering will reduce up to 84% of droplet spread, the main source of transmission of COVID. Additionally, in other pandemics the use of masks have actually promoted safer activity such as hand washing and physical distancing, acting as a reminder of the severity of the pandemic.
“We must carefully consider how we introduce masks. In several locations, such as pubs and restaurants, the use of masks will not be feasible or even possible. In these locations strict physical distancing of more than 2m and/or physical barriers should be used in order to protect the staff and other customers from the risk of asymptomatic carriers.
“We must consider those that will be disadvantaged by a mandate to wear masks, notably those dependant on lip-reading. For these individuals, moving to the safer distance of 2m and removing the mask in order to facilitate communication, or the use of masks with a clear panel are an alternative. However when faced with the risk of a disease that indiscriminately kills, as yet has no curative treatment, and is increasingly demonstrated to have long term health impacts irrespective of the severity of the original infection, we need to take all the help we can get to minimise risk.
“Of course, we need to a pre-specified point at which these are no longer are required. An incidence of less than 1 new case per million population per day is widely accepted as “viral eradication” and we would suggest this be the point that masks can safely be removed.”
Dr Rachel McCloy, Associate Professor in Applied Behavioural Science, University of Reading, said:
“After a period of very mixed messages, the Government have made the wearing of masks compulsory in some situations from the 24th of July. The success of this will depend on how the Government implement and communicate the change. It will most likely be successful if the changes are simple and logical, and if leaders show clear and consistent modelling of behaviour.
“Where it is most likely to fail is if the changes contain illogical exceptions or continue to promote mixed messages (e.g., shoppers must wear masks but they are not compulsory for retail staff; the rules apply to retail settings but not to other indoor settings where potential for contact is the same or similar), and where there are failures to consistently model the required behaviour from key public figures (as has happened with previous restrictions), which can promote an attitude of “if they can opt out, so can I”.
“Based on the current evidence base, wearing masks in situations where we cannot easily adhere to strict social distancing is a vital part of our efforts to avoid a second wave of Covid-19 – other countries around the world have been very successful in adopting masks, and there is no reason why, with clear policies and consistent messaging from the Government that the UK cannot show similar levels of success.”
Prof Keith Neal, Emeritus Professor of the Epidemiology of Infectious Diseases, University of Nottingham, said:
“The wearing of face masks in shops or enclosed shopping centres is one of those activities that should help reduce the spread.
“Lack of strong evidence of their effectiveness should not be considered a problem but the evidence is accumulating that they have apart to play in reducing transmission and also in protecting the wearer.
“Issues may arise on exemptions apart from age as people can claim to meet one of the exemption categories without obvious evidence. Exemptions like for anxiety can easily be used as an excuse given the apparent reluctance from too many people.
“Exempting young children is supported by the increasing evidence that they have a more limited role in transmission than adults. Many children could be encouraged to wear masks especially if they had their favourite characters on them.
“Enforcement need not be an issue as shops can simply refuse to serve non mask wearing customers.”
See other recent comments on facemasks at:
https://www.sciencemediacentre.org/expert-reaction-to-ministers-statements-on-facemasks-in-shops/
https://www.sciencemediacentre.org/expert-reaction-to-reported-comments-from-boris-johnson-that-they-are-looking-at-ways-of-making-sure-people-wear-face-coverings-in-shops/
All our previous output on this subject can be seen at this weblink: www.sciencemediacentre.org/covid-19/
Declared interests
None received.