How often does a face mask stop a virus?

[Goonshow]

I'm curious about this. It now appears to be widely accepted that a face mask helps stop a virus spreading. But how often does a single mask do the job and save a single infection?

I think it happens rarely. I don't think masks stop the virus much, if at all, and I find the blind acceptance that they do puzzling.

My initial guess is that a mask worn by someone each day will stop transmission of the virus less than once a year.

Anyone else care to give their thoughts?

It doesn't prevent infection. Just gives a false sense of security.

Apparently the whole worlds Covid particles would fit in half a coke can. Therefore, I truly believe most masks are useless (certainly the cloth or make your own adopted here).

Double masks worn tightly prevent 95% of infection according to Dr Faucci. Who is the top bod in USA l think

www.gov.uk/government/news/public-advised-to-cover-faces-in-enclosed-spaces#:~:text=COVID%2D19%20can%20be,transmission%20of%20the%20virus.

How could you possibly measure it?

Would you get thousands of people in every type of mask/face covering there is in every situation they could ever be in for every length of time they could be there, spray them with virus and see how many catch it?

Even then how would you know whether those who didn't catch it wouldn't have done anyway. I can't see how you would even begin to try and find out

Think about how much air must be able to pass through your bog standard 'going to Tesco' mask in order for you to be able to breathe comfortably. Then think about how small a coronavirus is.

I wear one because I have to and I don't mind it all that much, but I am under no illusions that it offers much in the way of meaningful protection.

I think they're useless.

If masks don't work, why do surgeons and dentists wear them?

I've just run my own model. Easily done.

if 25 million people wear a face mask for at least part of a day and that stops 25,000 cases, each mask will stop a virus once every 1000 days, or just under once every 3 years.

Masks were ordered to be worn in shops in July 2020 when reported cases were under 1,000.

They change them during ie an op or use a new one each time

Google it and see the many studies which prove that mask wearing is beneficial.

You can run the model easily. There are only 3 variables. If you specify the number of people wearing a mask and the number of cases you want to prevent, then this will calculate how often each mask must be worn to achieve the desired result.

royalsociety.org/-/media/policy/projects/set-c/set-c-facemasks.pdf?la=en-GB&hash=A22A87CB28F7D6AD9BD93BBCBFC2BB24

To everybody who believes masks do some good, please feel free to give your own estimate of how often you think your mask stops a virus.

There is no right or wrong answer, of course. We can never know.

But we can demonstrate some scenarios which we may find illuminating.

I'm no expert but my understanding is that while Coronavirus particles are far smaller than would be stopped by the weave on a mask, they travel on water droplets from breath, coughing and sneezing. Virus particles don't propel themselves - they must travel on something. The masks do reduce the spread of those water droplets, thereby reducing the spread of the virus. I have read that they are therefore more effective at stopping you from passing it on than they are stopping you from catching it. Like I say, no expert but that has been what I have surmised from a lot of research over the last 11 months!

This is such a random and weird thread.

Of course we can find out how much they stop droplets spreading. There’s so much research out there. Google it 🙄

If someone was near you had a cold, would you be happy for them to sneeze or cough on you? Do you think if they used a tissue to covering their mouth or nose then it makes no difference?

The virus is transmitted in respiratory droplets (not floating around on it's own, if you understand my meaning) and a mask absorbed a lot of these.

We have millions of people wearing masks in the UK. Aren't you curious about whether your mask is stopping a virus once a week or once a year?

I asked a couple of friends this question. At first they were reluctant to offer a guess (as are most people on here, so far) but one ventured once every 10 days.

If 25 million people in the UK are wearing a mask each day and their mask is stopping the virus once every 10 days, then we're stopping 2.5 million infections a day. I rather think it's less often than that.

Anecdotally my dd and her classmates wore masks throughout the autumn term

Out of her whole year group 40-50 kids tested positive across five classes

All were wearing masks when is class, outside not

Low effectiveness I would suggest, cloth masks, however so many other factors to consider (proximity, hand washing, effectiveness of putting on/removal of masks etc)

I think they give a false sense of security and without other measures are largely useless

Schools transmit because of large numbers of warm hosts (kids) and poor ventilation. Kids in un/poorly ventilated rooms for more than 15 mins at time

Face masks 🤷‍♀️

It will depend on the specifics of the situation and the type of mask.

For example a DIY cloth mask won’t prevent the passing of the same particles that a surgical mask would.
But either of them will catch a sneeze, small particles will get through some masks but not be freely blasted into the air.

Any covering will reduce what gets in or gets out, they also will reduce how much we touch our face.
(A face shield will protect eyes as well, but has wide open sides)
Combine a reduction of contact with mouth and nose, hand washing / hand disinfecting etc and the potential to pass on exposure is reduced

You can compare masks to clothing

It isn’t binary and you can’t attempt to calculate it using method you’re trying.

A mask will, to some degree, reduce the amount of viral particles released by someone into the surrounding air. By how much it does this is dependent on a huge number of factors (the fit, type of mask, how saturated it is etc etc)

Being exposed to a lower concentration of particles may not always stop transmission, but is associated with a less severe disease progression. For example - asymptomatic or mild case that does not require bed rest or hospital treatment.

Compared to other interventions to reduce spread, wearing a mask is low effort, cost & risk, and is associated with huge benefits on a population level.

You need to define ‘mask’. The effectiveness varies hugely

What nobody has mentioned so far is the prevalence of the virus. If the virus isn't in Tesco then the hundreds of masks in there don't have a chance to do their job.

It's quite clear that your mask isn't stopping the virus on a daily or even monthly basis. And as the number of people carrying the virus shrinks, the frequency of our encounters with the virus will diminish.

If the numbers fall to lower levels, the justification for mandatory masks reduces further. Rather than the last thing to go, as some suggest and which appears to be the orthodoxy, maybe they should be the first things to go.

I still believe that in a match between a mask and a virus, the virus wins every time...

Offering a guess is totally pointless and probably a bit dangerous.

What’s the point?