More layers in masks is better, say scientists

DOUBLE masking is being considered by government scientists, a senior official has suggested.

Dr Susan Hopkins, of Public Health England, said that people should ideally wear masks made up of three layers to get the best protection.

However, in response to a question about a growing trend of wearing more than one mask in the US, she said a specialist committee was in an “ongoing discussion” about updating the advice.

It follows the recent publication of a study by the US Centres for Disease Control and Prevention which found that the best way to stop infection was to wear a cloth mask on top of a surgical mask. Leading UK scientists have also said that two masks are likely to make a difference, although not by offering double the protective effect.

Good quality protective face masks are made up of three layers, but many come with less protection, leading scientists to question whether a two-mask approach is desirable.

Speaking at last night’s Downing Street press conference, Dr Hopkins said: “The more layers you have, the better. And so that we recommend at least two layers in the UK and ideally three layers in a mask.

“We have got a face masks and face coverings advisory group who meet on a regular basis, and look at new and emerging evidence, and the US has looked at some of that evidence as well.

“We think one mask that has more than two layers in it is currently effective for the vast majority of the population.”

The US study showed that transmission of the virus could be reduced by up to 96.5 per cent if both an infected and uninfected person wore a tightly fitting face covering.

The analysis compared wearing no mask, a poorly fitted surgical mask, a cloth-only mask and a double mask in a simulation of the spread of respiratory drops between an infected and uninfected person.

The research concluded that the best way to stop the spread was to wear a cloth mask on top of a surgical mask or to wear a surgical mask on its own but tie the straps where they meet the mask to ensure there were no gaps.