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What if this virus' preferred way of transmission is not through big droplets, but the tiny airborne droplets?
Well, this has been a matter of quite some study for quite some time. Example.
It is carried on respiratory droplets, and these droplets come with a distribution of sizes. There are more viral particles within larger droplets (the number is proportional to the volume of the droplet or radius cubed), while at the same time there are more smaller droplets which also travel further.
Cloth masks protect the wearer against larger, shorter range droplets, as well as blocking many droplets from being aerosolized in the first place. If you watch slow motion footage
or do simulations, you can see that many of the smaller droplets are formed upon fragmentation or subsequent evaporation in the air after they are expelled, so face coverings work even better than you might think.Epidemiological studies
show the effectiveness of masks under various conditions, especially in indoor spaces like restaurants and office buildings. A trip to the grocery store or doctors office is much safer where everyone is wearing masks. A trip to a gym or indoor bar is far less safe, where more people are not wearing masks. I see this over and over again with the contact tracing efforts, too.
I think the discussion about masks is polluted by oversimplified thinking, that they either they block the relevant size particles or they don't. It's more nuanced than that.
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Strict lockdowns will send people indoors, possibly making things much worse.
To me it seems the opposite. We have more than a year of data from all around the world. Whenever a city or region went into lockdown, they traded exponential growth of new infections for slower growth, or even exponential decay. In other words, R was decreased. We saw this first in China, then Italy, then Seattle and NYC, the UK, Israel... and right now it is happening in India. New Delhi went into lockdown on April 19, and we are now starting to see the effect show up in the new cases curve:You are hitting on a piece of truth in role of indoor spread, however. Lockdown does increase the fraction of transmissions that occur indoors. In the height of NYC's lockdown, for instance, contact tracing showed that about 3 in 4 new cases were due to spread between family members in their homes. (Before the lockdown it was about 1 in 4.) At the same time, it reduced the total rate of transmissions (the effective R value), and the rate of new cases decreased exponentially.Basically, lockdowns don't change very much the probability of transmissions indoors. It is very hard to avoid an infected person from infecting their family with our without a lockdown. But lockdown does dramatically reduce the risk of transmission throughout society. Hence, fewer people get infected, and fewer people bring it home. And given the nature of exponentials, changing the growth rate has a huge effect. Every day you don't make the decision to lock down costs exponentially more lives.I'll take exponential decay over exponential growth of new infections any time. I'll even take a slower growth if it's the best that can be done (e.g. India last year.)
A good way to mitigate indoor transmission should be obvious. As you say,
midtskogen wrote:I'm kind of stunned to hear that this is not being recommended there. Over here it has been the norm since last summer when things began phased reopening. Most restaurants serve outdoors, or if they are open for indoor dining, they open up the doors and windows and typically have fans going. Most businesses keep the doors wide open. When people need to go into one another's homes they open windows. Most people seem to know that crowded and poorly ventilated indoor spaces are more dangerous.That being said, people's behavior varies a lot by region. Some places seem less aware of what's going on or how to handle it. In other counties and states more people act as if there is no virus. No surprise then that they have higher per capita rates of death, even when they have a lower population density.
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If the climate allows it (as in much of the world), people could be told to keep windows and doors open as much as possible to keep a steady draft through all buildings. But I've not heard this recommended by any authorities. Isn't this a no-brainer?
Last summer my mother and many of her friends wanted to return to do volunteer work at a thrift shop up in town, which received very high traffic from a wide community, in a compact indoor space. They are elderly and highly vulnerable, and were prepared with masks, face shields, and sanitizer, and a good plan for reduced operating capacity and social distancing. I still thought they were being insane. It is too much time for them to be working in that kind of environment. I told them I did not think it would be enough, and helped them upgrade their air filtration unit to be rated for viral particles. Even then I was not crazy about the idea of them working in there, and talked my mom out of working there at all. Thankfully, though, nobody in the shop has gotten sick (even as many cases have continued to occur across my community). Apparently, they are either very lucky, or their methods are working. Now they are all fully vaccinated so the risk is even less.