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?

Mask wearing is shown to reduce community transmission. The evidence for this has been growing throughout the pandemic.

You can't calculate how much one mask on one person would reduce transmission by as it is hard to figure out how much risk there is in a single interaction without one, as some people are superspreaders, some people seem to spread asymptomatically and others don't and age may be a factor but we don't entirely understand how yet.

My own view is that...etc

This thread is a bit Twilight Zone....

Honestly it is like arguing nuclear physics with a toddler.

Your calculation doesn't work OP as they don't take into account the fact the level of compliance.

One person wearing a mask in a group of 100 people will have less impact than one person out of 90 people wearing masks in a group of 100.

This is partly as masks are designed to reduce asymptomatic spread and if there are one or two people with covid in that group of 100 (or EIGHTEEN as it was round here a month or so ago) then they are more likely to be masked in the group where 90 people are masked compared to the group where one person is masked.

It's much like vaccines. One jab doesn't amount to much if you are the only person having it, but if you are one of the people who has a vaccine and brings the total amount of the population vaccinated to over 80% it arguably has a huge effect.

I have no idea. But blind acceptance is all the rage, and face masks no exception.

Mask wearing is shown to reduce community transmission. The evidence for this has been growing throughout the pandemic.

I would say the evidence has gone through stages:

• March 2020 - masks do not work
• Summer 2020 - masks reduce community transmission by 60%+ (as evidenced by the German study from city of Jena and multiple US based research papers) and they are our "ticket to freedom". We will all be able to go back to normal if we wear masks.
• Winter 2020/2021 - masks do work but it is only one of multiple measures (as per PHE/SAGE reports) and there are more important factors at play, e.g. ventilation.

@Haffiana

My own view is that...etc

This thread is a bit Twilight Zone....

Honestly it is like arguing nuclear physics with a toddler.

Or playing chess with a pigeon...

@TheDailyCarbunkle

I understand what you're saying OP, but I don't think many people on the thread do - they're just not understanding what you're getting at. Your reasoning might seem clear to you but it's not a type of thinking a lot of people are capable of, so it's going over people's heads.

I agree entirely with what you're saying.

40% of infections are occurring in hospitals, locations with strict infection protocols in place and proper PPE (though admittedly there have been failings and gaps on that side of things), so that's an interesting scenario to run your numbers on.

Well you would wouldn't you. Being in the same club and all.

😄😄😄

Wow. Some seriously arrogant people on this thread, arguing against masks because in reality they just don't want to use them.

@wintertravel1980

1. It has never been the case that the WHO has claimed that masks are all that is needed, or a 'ticket out of here'. In June it stated that there was observational evidence that masks (three layer fabric) could have an impact on community transmission. It has always been understood from early on that ventilation plays a significant role from early on in the pandemic among the scientific community.
2. Evidence has grown as more research has been done. That is not the same thing as stating that evidence has shown impact of mask wearing in the community is stronger than initially thought.

@Ohnomoreno

I have no idea. But blind acceptance is all the rage, and face masks no exception.

Actually, although there isn't any solid evidence that enforced public mask-wearing prevents asymptomatic viral spread (lets, face it - people with symptoms are not out and about), I would hope that when we masks are not required, that those who still want to wear them for a while can do so without being mocked.

I posted a study on another thread about masks; I don't have it to hand right now.

However, I used to watch the covid briefings daily in last spring (when I was very scared about catching it) and a lot of the questions were about masks. Back then Jennie Harris said that the evidence (based on the size of viral particles) wasn't good enough to ask people to wear masks.

www.independent.co.uk/news/health/coronavirus-news-face-masks-increase-risk-infection-doctor-jenny-harries-a9396811.html

I hope that when the F1 restarts the presenters don't have to wear masks again for their interviewing - outside - but, alas, I fear this will still be another year of the mask...

Sorry, that was a v random thought, but I look at mouths when people speak much more than I previously realised (Aspie, so probably not that surprising) so I get v bothered seeing masked outside interviews. Might as well be listening to the radio.

Isn't Jenny Harries the one who thought kids facing forwards (even if sitting shoulder to shoulder) would magically prevent them infecting each other, because, presumably, she didn't realise they had necks that moved? Despite the fact that basically all other scientists said this was clear and obvious nonsense.

And has has been amply shown to be wrong by rocketing secondary and primary level rates of infection pre-Xmas.

I understand what you're saying OP, but I don't think many people on the thread do - they're just not understanding what you're getting at. Your reasoning might seem clear to you but it's not a type of thinking a lot of people are capable of, so it's going over people's heads.

@TheDailyCarbunkle, you're absolutely correct - many of us are capable of critical thinking. Not many on this thread are capable of this at all. You seem intelligent, though - just a little blinkered and stubborn on some issues. I know what the OP is trying to say, but her 'science' is all over the place.

Rather hard to count how often something doesn't happen?
At least people seem to have got the message now and I see fewer people with them carefully arranged around their neck or hanging from one ear.
And they certainly made a great job of keeping my nose warm, even when it was so cold last week.

To show what a bizarre and unscientific way of looking at things this is, let’s just take the mask out of the equation.

If the r number is 3, then the average infected person will pass Corona to 3 people. Over the last year, maybe 15% of the population have been infected, so over 1 year, your ‘average’ person will pass Corona to 0.45 people at current rates.

If masks stop 20% of spread, the average mask wearer will only prevent .09 infections per year.

That does not mean it is ineffective, though, as, at population level, they will still be saving maybe 10,000 lives and maybe preventing 1 million people being infected.

Is the idea of this thread to persuade unscientific people that it is a ‘really small number’ ergo (incorrectly) let’s ditch the masks?!

Last year the Norwegian government worked out the idea you are trying to describe based on the prevalence at the time and an assumption about how effective masks are and how many people are asymptomatic.

www.fhi.no/globalassets/dokumenterfiler/rapporter/2020/should-individuals-in-the-community-without-respiratory-symptoms-wear-facemasks-to-reduce-the-spread-of-covid-19-report-2020.pdf