"It's all about minimising risk"
Since Monday, wearing a facemask as soon as you enter any university building has been compulsory at ETH Zurich. In this interview, Dr Leonhard Sigel, head of the Occupational Medicine and Health Protection section of SSHE at our university, explains why facemasks are a necessary and sensible measure.
Dr Sigel, we were told in March that facemasks were not particularly helpful and should be reserved for healthcare professionals. But now facemasks are mandatory at ETH. Why this turnaround?
Back in March there was a dramatic shortage of facemasks in Swiss hospitals, as I know from personal contacts. It was absolutely essential to avoid the sort of situation seen in Italy, where medical personnel died from contracting COVID-19 due to a lack of personal protective equipment (PPE). We therefore decided to donate to the government some of the masks we had in reserve for combating pandemics. So at the time it was perfectly correct to say that facemasks should be reserved for healthcare workers. In the meantime, supply chains are back to normal and there are enough facemasks to go around.
Are you aware how annoying people have found the mixed messages on facemasks?
Yes, of course. We always like to have things set out in black and white. But in the case of COVID-19, there are a lot of grey areas. Initially I did not support the idea of the general public having to wear a facemask, as the approach in occupational medicine is first to try and find technical and organisational solutions, as facemasks tend to get in the way while working. But over the course of time I have learnt that facemasks are no longer a topic limited to occupational medicine, but have become a public health issue.
What do you mean by that?
There has been a universal realisation that wearing a facemask is essential. Chinese students and lecturers have also repeatedly told me that things would work out fine if we wear masks. Asian countries can draw on many years' experience of epidemics and there are already good reasons why they are so keen on wearing facemasks.
So does that mean facemasks offer protection?
Yes, all types of facemask provide protection to other people, and to a certain extent to the wearer as well, depending on the type of mask (see the DownloadInformation sheet on Types of Mask). We often want things to be perfect, but quickly realise that masks do not offer full protection, so we need to employ other measures such as physical distancing. But now more than ever people realise that our goal must be to minimise risk. And we can come very close to achieving this goal, even if surgical masks only reduce the risk by 80 percent.
Is it true that wearing a mask only makes sense if everyone does it?
No, the effect is already very good if 95 percent of people wear one. There will always be exceptions, as some people have very good reasons for being unable to wear a mask, and it's important not to give them strange looks or even stigmatise them. I am very confident that we will be able to persuade a very high percentage of people to wear masks.
What should people do if they are unable to wear a facemask for personal health reasons?
I've already had requests from ETH members for exemptions. We have to consider each case very carefully, as our priority is to protect the actual wearer and other people. Their line manager or supervisor should at least be informed. And then I advise anyone affected to discuss the issue with their doctor at their next consultation. This is because those people experiencing problems with wearing a mask, for example pregnant women or anyone with a chronic respiratory condition, belong to a group of particularly vulnerable people and therefore need to take even stricter protective measures. In their case, the best choice would probably be to wear an FFP2 mask. Unfortunately, these can make it slightly more difficult to breathe freely, which limits the time they can be comfortably worn.
All we have to do is take a practical approach. The most important thing is that wearing a mask should become an integral part of our everyday routine. Leonhard Sigel, Head of the Occupational Medicine and Health Protection section of SSHE
How will the wearing of facemasks be controlled on campus?
We are following the principle of keeping an eye on everyone and speaking to people. Staff from Facility Management and Security are patrolling the campus and will remind anyone not wearing a mask that it is compulsory to do so. They will also be carrying masks they can give out to people who do not have their own. But it's also up to all of us to remind anyone we see not wearing a mask.
Why am I allowed to remove my facemask when I arrive at my final destination?
As I already mentioned, the measures are intended to minimise risk. The rule of keeping a physical distance of 1.5 metres between people is also designed to reduce the level of risk. The more people – and different groups of people – returning to university buildings, the more crowded it will become in corridors, in queues or just standing around. By wearing a facemask, we reduce the higher risk of infection that exists in indoor spaces. As soon as I reach my destination, I can control my immediate environment much more effectively – by ventilating a room and keeping my distance, for example. At that stage, not wearing a mask becomes acceptable.
Do I really have to put on a facemask if I just go from my own office to see my colleague across the corridor?
That depends. If the corridor is frequented by many people (and different groups of people), then wearing a facemask is advisable. But if the office is located at the end of a corridor not open to the public, then not wearing a mask is okay. I think we need to use common sense in how we implement each rule. It is impossible to cater for every individual scenario.
If wearing a facemask is compulsory, will ETH Zurich provide them free of charge to employees and students?
Facemasks with the ETH design will be available to buy at a discounted price in the ETH Store from the start of September. But the ETH Executive Board has decided that for cost reasons staff and students must buy their own masks. Most of us already have a mask as they are mandatory in both shops and public transport in Zurich. But if the nature of their work means an ETH employee needs a facemask due to unavoidable close contact with other people (for example in a lab or workshop), masks are considered to be part of personal protective equipment and will be supplied free of charge by the relevant departments.
Aerosols are increasingly seen as an infection risk. What protection do facemasks actually provide against them?
Facemasks certainly provide some protection against aerosols, but that obviously depends on the type of mask. FFP2 masks are excellent at blocking aerosols in both directions. Surgical masks also offer 80% risk reduction, while the main purpose of community masks is to act as a barrier to contain aerosols when people talk. Naturally these two types of mask never provide a tight enough seal to prevent aerosols getting through.
What other action can be taken against aerosols?
Always ventilate as much as possible! Here it's not important to spend too long thinking about the correct procedure – simply throw the doors and windows wide open and let the air circulate. This creates air movement and helps reduce the aerosol concentration, which is basically always a good strategy. Another way to prevent the spread of aerosols is to install partitions made of plexiglass. And physical distancing obviously helps as well. People should avoid speaking too loudly and definitely refrain from singing. At the moment I would also advise avoiding small indoor spaces with no ventilation, such as elevators. Some infections through aerosols have already been traced back to elevators, so my advice is to use the stairs instead.
Should (or can) I use a fan in my office?
That's a hotly debated issue at the moment, and no research is available yet, as far as I know. Personally, I would say that if the fan is only directed onto one single person and towards an open window, there's no problem. However, it's important that the fan does not blow the air over several people.
What about airing laboratories and meeting rooms with no windows? Can I be sure that ventilating the room will not accidentally spread the virus?
Some months ago the Facility Management Department already switched the fresh air supply to maximum and turned the circulation rate down as low as possible. Coupled with the rules on physical distancing and the maximum occupancy specified for every room, we are able to achieve a good level of healthcare protection.
Is it dangerous to wear a mask more than once, and to wear it on your arm or slung around your neck, as you often see?
The ideal approach would obviously be to always wash your hands before putting on the facemask, and then never touch it again. But as an occupational health expert I take a pragmatic view, and I know that solutions which are too complicated for people do not tend to work. The Federal Office of Public Health has made a recommendation which I think is very sensible: keep your facemask in a paper bag – not a plastic one – when you are not wearing it, to allow it to dry. I must confess that I also carry my mask on my arm when I'm outside, but I wouldn't advise wearing it around the neck. You can even attach it to your belt. The rule of thumb is that facemasks should never touch anyone else, and when you put it on or take it off, only ever touch it by the ear loops, bands or ties. All we have to do is take a practical approach. We are not surgeons operating in a hospital. The most important thing is that wearing a mask should become an integral part of our everyday routine.