What’s the story with face masks?
The topic of whether or not to wear face masks has caused a lot of confusion since Covid-19 appeared. This post is a summary of what we know and our advice (22 June 2020)
The first important point is that all those public health measures which are recommended (restricted movements, hand washing, physical distancing, face masks and more..) are about reducing risk rather than eliminating risk, and should be looked at in that context.
Reducing the transmission of Covid reduces the number of people infected which in turn reduces the number of people who are seriously or die.
The World Health Organisation recently asked the medical journal Lancet to review all studies about the public health measures to see what worked.
There seems to be reasonable evidence for the benefits of both physical distancing and face mask, however some of these results are difficult to compare because they were measuring different sets of circumstances e.g. in hospital or community, different types of mask or different physical distances.
So, let’s get back to the basic science. The currently best available evidence suggests that Covid-19 is most commonly spread by respiratory droplets, especially when people cough and sneeze, entering through the eyes, nose, and mouth, either directly or by touching a contaminated surface. Droplets travel a certain distance in the air when we talk, much more so when we cough or sneeze. Therefore we cough or sneeze into a tissue or our elbow, we wash our hands to protect against surfaces. But keeping a distance apart reduces the risk of being droplets being passed between people.
Should that be 2m or 1m? The simple fact is that less droplets will travel 2m compared to 1.5m compared to 1m. No distance is “correct” but the more we aim for the 2m advice, the lower the risk.
So back to face masks. The biggest benefit of facemasks is to prevent spread of droplets from the wearer to those close to them.
So, we wear masks mainly to avoid passing on Covid-19 rather than to avoid catching it. There is some protection from other people (more so with expensive surgical masks), but it’s mostly the other way around.
“But I haven’t got Covid, so I don’t need to wear a mask”. The problem here is that we don’t know when we might catch Covid, and there is good evidence that we can spread it before we start to feel unwell. So you could unwittingly infect someone who’s vulnerable or caring for a vulnerable relative.
Of course, the use of face masks should not be viewed in isolation, and the risk of infection is higher at different times, so let’s just apply a bit of common sense. The most benefit is likely to be obtained in more crowded environments with less circulating air, therefore there are stronger recommendations for the use of face masks
- in shops
- on public transport
- healthcare settings (because of the higher risk with ill people)
Therefore we would also like face masks used in the surgery (by both doctor/nurse and patient)
In summary, the public health advice is all about reducing the amount of Covid-19 in the community, and we’re all being asked to play our part to protect ourselves, our families and our communities. To varying degrees, we reduce risk to ourselves and others by keeping our distance, avoiding unnecessary trips, washing our hands and wearing face protection.
For more background information, please follow the links below