July 15, 2020

expert reaction to reported comments from Matt Hancock that face coverings will not be made mandatory in offices

The Secretary of State for Health for the UK, Matt Hancock, said this morning on the BBC Radio 4 Today Programme that face coverings will not be made mandatory in offices.

Dr Jenna Macciochi, immunologist, University of Sussex, said:

“When it comes to masks it seems to be a divisive issue.  Masks themselves don’t pose a health risk but in an emerging pandemic we need to remember that things change with regards to public health messaging.  In light of what we know now I think masks are a sensible addition to other measures.  We know much more now than we did a few months back.  Cloth masks may reduce respiratory droplets which we know is a route of transmission.  It’s little cost and negligible risk to the wearer, but there is potential for significant societal gain therefore the balance tips in favour of masks. 

“A systematic review of masks in the community (albeit not home-made ones) shows they slightly reduced chance of developing covid when both infected and uninfected wear them but are not a substitute for social distancing and handwashing, good hygiene and tissue etiquette.

“One of the challenges is that we have little scientific evidence on how well cloth masks actually work in the general public because they are all made from different materials. 

“From previous epidemics we do know that face coverings provide some protection to healthy people in close contact with cases in the community.  Just because there is an absence of evidence does not mean they are not protective.  We need more research to clarify these uncertainties.  If home-made we need to consider breathability and maintenance and the advice is never share it, change regularly and remove without touching the front. 

“We need to be prepared for things to change rapidly with the covid situation, much quicker than with other public health messages.  But this also breeds scepticism.  There may also be people for whom mask wearing is not appropriate due to an underlying condition.  But if we want to open businesses and have some semblance of normality then we need to use all precautions available to us.  Overall face coverings are important but you cannot say more important than other measures, all measures play an important role in reducing risk.

“With regards to indoors and air conditioning, we know that the main route of viral transmission is through droplets that are generated when people breathe, talk, cough and sneeze. If a person is infected these droplets can contain a virus.  This is the main route of transmission and is particularly an issue when people are in close proximity of where there are surfaces that are touched often by many people.

“There is however emerging evidence that transmission can occur through small aerosols that stay in the air longer than droplets.  Although covid doesn’t primarily spread this way, it may be a route of transmission in certain busy enclosed environments with poor ventilation.  All measures are going to be important but it is impossible to eliminate all risk.  One small step would be to ensure that all buildings have good ventilation where possible.”

Prof Richard Tedder, Visiting Professor in Medical Virology, Imperial College London, said:

“There seems to be a misunderstanding about face masks partly based on the misconception that Sars CoV 2 is an airborne infection which simply is not the case.  It is transmitted by droplet spread and whilst these may be carried further by air movement  they remain as drops of fluid, sometimes actually chunks of spittle, explosively shed from the upper respiratory tract during speech, laughing or coughing.  These are common activities in the office environment and the wearing of masks will likely capture the majority of these projectiles, actually providing safety to others in the office environment rather than protecting the wearer.  The wearing of a mask is likely to be more effective than trying to encourage the use of a handkerchief and equally effective at catching expectorates (better known as gobs of snot).”

Prof Rowland Kao, Sir Timothy O’Shea Professor of Veterinary Epidemiology and Data Science, University of Edinburgh, said:

“An important point about the difference between offices and shops is that, while offices may in fact be higher risk to particular individuals, they are less likely to expose a large number of people to COVID-19 than interactions in shops or public spaces – while this will be workplace dependent of course, they will tend to expose a smaller group of people for a longer period of time, whereas interactions in shops will expose many people for a shorter period.

“Also, should an infection be detected the role of contact tracing is going to be vital in preventing a large outbreak.  As the people you meet in offices are much easier and more likely to contact trace than the chance contacts in shops, reducing infections due to casual contact (as wearing face masks in shops will do) will play a big role in allowing contact tracing to work well.”

All our previous output on this subject can be seen at this weblink:

www.sciencemediacentre.org/tag/covid-19

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