Do face masks work? Here’s what the science says
One of the major scientific discoveries of the past few months is that there are huge numbers of people with the disease who are asymptomatic – maybe even as much as 80 per cent.
Studies have found that viral load – the amount of virus present once a person has been infected and the virus has had time to replicate in their cells – peaks in the days before symptoms begin and that simply talking is enough to expel infectious droplets.
A study by the National Institutes of Health in the US, using high-speed video, found that hundreds of droplets ranging from 20 to 500 micrometers were generated when saying a simple phrase. But nearly all of the droplets were stopped from spreading if the mouth was covered with a damp cloth.
Adam Finn, professor of paediatrics at the University of Bristol, said: “Most masks will do a much less efficient job of protecting the wearer from breathing in droplets and no mask will stop you infecting yourself with your hands.
“In fact, if you spend a lot of time touching and adjusting your mask and your hands are contaminated, they could even increase your risk of self-inoculation.”
The situation in the UK?
To make the situation more confusing, recommendations across Britain have varied considerably.
On April 28, Scotland advised the public to wear face masks in enclosed spaces where social distancing is difficult to achieve, and imposed mandatory wearing on public transport as of June 22. On June 9, Wales also recommended that face coverings could be used where it might be difficult to stay two metres away from others and advised using three-layer, non-medical face coverings.
England made wearing masks mandatory on public transport on June 15 and extended this to shops and supermarkets from July 24. Some scientists believe there is still not sufficient evidence to advise widespread use.