A couple of years ago, if you had seen people in the streets or the shops wearing a mask, you might have thought they were a bit eccentric. Nowadays, the opposite is true. We have become entirely used to this.


But will we go on wearing masks when the immediate threat of the coronavirus has receded? I suspect not. Unless COVID-19 rears its ugly head again, I can’t see those masks going anywhere other than the back of a drawer. This is a shame, because I suspect we will see a lot more flu around in six months’ time (last winter saw remarkably few cases) and wearing a mask could make a difference.

Wearing a mask has, unfortunately, become almost an ideological statement, and certainly a cultural one. One of the clear differences between countries that controlled the initial spread of the virus, like China, South Korea and Taiwan, and countries that didn’t was the fact that in the former people were actively encouraged to wear masks outdoors and were happy to do so.

To reduce the spread of COVID-19 or other respiratory viruses, the masks don’t even have to be that sophisticated. Last year, Prof Trish Greenhalgh, of the Nuffield Department of Primary Care, and research scientist Jeremy Howard, carried out a comprehensive review on face masks which was published in the British Medical Journal and concluded that “masks are simple, cheap and potentially effective”.

The reason why wearing simple masks has such a big impact on transmission of the virus is not just because they protect the wearer (although there is mounting evidence they do, particularly if someone coughs directly in your face), but also because they can dramatically reduce the amount of droplets an infected person sprays around.

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The superpower that respiratory viruses possess is their ability to infect your nose and throat and then jump to other people whenever you sneeze or cough. What wearing a mask does is dramatically reduce the risk of that happening. In fact, as Greenhalgh and Howard say, “If you have COVID-19 and cough on someone from eight inches away, wearing a cotton mask will reduce the amount of virus you transmit to that person by 36 times.”

A hand reaching for a surgical mask, hanging next to a set of keys © Jason Raish
© Jason Raish

There is increasing evidence they will also protect you. For a study that was published as a pre-print in January this year, researchers from the department of engineering at Cambridge University exposed people to controlled amounts of harmless droplets while they were wearing different sorts of masks.

Impressively, even homemade cloth masks blocked out between 62.6 per cent and 87.1 per cent of fine particles. In fact, they were far more effective than most people who were surveyed as part of the study believed. As the researchers pointed out, even if that means some viral particles get through, it means you are less likely to get a serious infection.

So keep those masks. Come next winter, when we get the annual flu outbreak, you might feel the need to use them again.

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Dr Michael Mosley is former medical doctor, health writer and BBC presenter. He’s best known as presenter of Trust Me I’m a Doctor on BBC Two but has also written a number of bestsellers about personal health and medicine, including The Fast Diet, Fast Asleep and Fast Exercise.