[seanmcdirmid]

No one has done a controlled study on this, so no one really knows. It ranges from zero to many.

The reason government and medical signaling on the subject has been so mixed is that it isn’t apparent they are very effective, especially the jury rigged cloth masks that people are using.

[saiya-jin]

Even basic mask works quite well in stopping infected person spreading it further. This isn't some recent covid-related revelation, but long known fact. To say it for the 1000th time - this doesn't make you magically virus-proof, but significantly lowers the infection rate of those who have it. On large enough scale, this behavior makes significant difference in infection rates.

I have yet to see a single western leader to recommend those masks for all the interactions (indoor at least). Case point - yesterday I went shopping in fairly large supermarket in Switzerland, and there were maybe 5 other customers (out of at least 100 in the store during that time, probably close to 200 plus all the staff) wearing masks, or gloves. People at least often kept their distance (not always possible in aisles), but that's about it. In a country which has one of most per-capita infections globally.

Why? They rely heavily on politicians doing right stuff. Mostly it works, but in these times politicians prefer keeping economy running (they delayed strong measures when things were getting worse than bad in Italy few kms from their border due to fear of financial impacts... well now they are worse but delayed by few days).

[Tiksi]

New York and New Jersey have gone past recommending masks, and have mandated them for anyone out in public, along with limiting the number of people allowed to go into a store, and a 6ft distance in any line/queue.

[hilbertseries]

Los Angeles has mandated you have to wear a face covering when going into essential businesses.

[thowfaraway]

There are many controlled studies on other respiratory disease like the flu, and some on other corona viruses like SARS the show high efficacy of masks. If you doubt the science, fall back on common sense. A respiratory barrier is going to have some value in diminishing the ability of a respiratory virus to spread.

https://www.preprints.org/manuscript/202004.0203/v1

The reason government and medical signaling on the subject has been so mixed is that it isn’t apparent they are very effective

The reason signaling has been mixed is because they were trying to preserve supply for medical professionals. The reason that medical professionals need them is because they work.

[smileypete]

>No one has done a controlled study on this, so no one really knows. It ranges from zero to many.

Can't remember seeing any controlled studies on the efficacy of social distancing either.

Many of the healthcare professionals in the countries that dealt with SARS are calling for universal mask wearing. I'd much rather trust their intuition and judgement than governments and media outlets passing the buck to the WHO.

[danans]

> Can't remember seeing any controlled studies on the efficacy of social distancing either.

No, but we have mountains of evidence from respiratory diseases throughout history, including the common cold and seasonal flu, that distancing lowers transmission.

It's why people are encouraged to stay home from work when they are sick, and why in normal situations, people in lines of work where they cannot afford to stay home from work get sick more often.

Social distancing is one of the oldest public health protocols we have for disease transmission control.

Sure, many old practices for disease prevention amount to nothing but old wives tales, but social distancing likely isn't one of them.

[pps43]

> no one really knows

Healthcare workers wear masks. I'm pretty sure they have a pretty good idea whether masks work.

[lonelappde]

Tools work, of course. But they don't always work well when handled by untrained amateurs.

[pps43]

They don't have to always work well. If Alice's mask stops half the particles and Bob's mask stops half the particles, the chance of Alice infecting Bob is now 4x lower. 50% is not as good as 95%, but surely better than 0%.

All we need to do is bring the reproductive number below 1, not necessarily all the way to 0.

[brewdad]

I've also seen a tendency for people to disregard all of the other social distancing measures now that masks are more common. Squeezing up next to someone to grab a bunch of parsley rather than waiting 5 seconds for them to move on. Tons of face touching from adjusting masks too.