MARK Innes (Letters, July 23) states that vaccines are fully tested and usage policies are based on sound scientific evidence. However, he writes, “the policy for mandatory usage of 'cloth face masks/coverings' seems to be based on circumstantial assumptions.”

This is not true. Professor Melinda Mills, Director of the Leverhulme Centre, did a comprehensive study on the usage of masks states categorically: "The evidence is clear that people should wear masks to reduce virus transmission and protect themselves.”

The study also found that cloth face coverings are effective in protecting the wearer and those around them.

She stated that face masks need to be seen as part of "policy packages" with other measures such as social distancing and hand hygiene, and clear and consistent policies and public messaging are key to the adoption of wearing face masks and coverings by the general public.

Let's be clear though, even if the evidence was anecdotal at this stage, face coverings would fall into the "pragmatic" category because any downside (of which there is virtually none) is far exceeded by the potential upside. You know? Coughing, sweating, lungs filling with fluid and respiratory assistance by way of ventilators which have about a 30 per cent risk of complications; and of course, death.

Mr Innes goes on to state: "Only N95 respirator masks are of any help in the prevention of respiratory disease." This again is not true. The N95 respirator mask affords protection only to its wearer. It is used in areas of high Covid-19 infection, ie hospital wards. This front port does not filter exhalation, only what is inhaled. On breathing in, air is filtered. When you breathe out, it is discharged via the front valve but is unfiltered. Why? To protect the wearer from catching Covid-19, like doctors and nurses. There is no downside to them expelling their breath into the surrounding environment because they are in a ward with patients who already have the virus.

The reason for wearing a face-covering is not for your protection. The virus, while small enough to get through a mask itself, does it by hitching a ride on respiratory droplets expelled when you breathe and they are caught by the face covering. The face-covering is not to stop you getting Covid-19. Its intention is to stop you from infecting others in the event that you catch it.

WHO guidance has been updated to reflect this and so has the Scottish Government guidance. Jason Leitch was not CMO at the commencement of this but his comments since, with respect to the N95, were limited to those in the shielding category and to health care workers, for whom N95 masks are recommended. For everyone else, it is face coverings.

There is nothing Orwellian about-face coverings, they are proven to work. After all, they are the same type of masks that surgeons wear in the operating theatre to stop them coughing into your chest cavity. They are proven to work, more so than seatbelts. The first face mask was used in surgery in 1897. The first seatbelt wasn't created until 1959.

Keep your distance, wear your face covering, give the gift of life.

Martin Keatings, Dunfermline.

THE language used in the announcement this week, and which appears on your front page on Friday ("Shielders are allowed out as FM ‘pauses’ measures", The Herald, July 24), which stated that those who have been shielding are now "allowed" out, is disturbing. Who gives the First Minister and her Government the authority to dictate to sensible people? Presumably she really meant, " You may now go out safely, if you wish". If so, she should have said so in a kindlier manner.

Elma Cunningham, Coatbridge.