Letters

Ongoing saga about wearing face masks

December 5th, 2020 5:10 PM

By Southern Star Team

Share this article

SIR – In reading MacDonald’s letter in your paper (dated November 21st), I was led to wonder if he had actually understood either of my previous letters, and I resent his insinuation that I am a liar.

First, a little calculation. The current positive test rate for Covid-19 in Ireland is currently averaging about 500 a day (an overestimate, I know). If you accept my earlier assumption of about 50% detection, this means there are about 1,000 new cases a day in the country.

Over the 14-day period widely quoted, this suggests that there are about 14,000 people in the country currently infectious with Covid-19 – about 0.3% of the population – three in a thousand.

The thrust of  MacDonald’s argument is that the wearing of a face mask reduces the risk of onward transmission from this 0.3%. Indeed, a number of studies have been carried out on droplet transmission outward through a face mask when correctly worn, showing a range of effectiveness depending mainly on the mask construction, and all show some effect on outward transmission, even the humble scarf.

However, throughout my letters I have been trying to show the potential for a face mask worn past its saturation time to increase the risk of infection to the wearer, and the paper to which I referred dealt with this matter.

I originally estimated about 15 minutes based on my own experience – this may be too low, but the principle still applies.

In other words I have been trying to bring home to people – the 99.7% currently not infected – some of the potential dangers of using face masks incorrectly and overlong (thereby potentially increasing their own risk of infection) and regarding them as a ‘magic carpet’ solution. I admit to myself using a face shield rather than a face mask – apart from its other advantages – it is a 100% barrier against spray transmission of the virus both ways, although diffusion transmission can still occur.

I do think that anyone who wishes to criticise a position – whether they are qualified in critical reasoning or not – should first take the trouble to read and understand what is being said.

John Lucas, MA (Oxon),

Gurteen, Ardgroom, Beara.

Tags used in this article

Share this article


Related content

Subscribe

to our mailing list for the latest news and sport:

Thank You!

You have successfully been subscribed to SouthernStar newsletter!

Form submitting... Thank you for waiting.