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Comment by quantdev | Hacker News Reader

The primary transmission route in inhalation in close proximity to an infected person. Yes, it can persist on surfaces, but this hand-washing meme is mostly a result of (1) it costs nothing and may help, so we should try and (2) masks are supply limited and the healthcare industry doesn't have enough. In reality, if we had an abundance of masks, masks would be more important than hand washing. As it stands, we reserve them for HC workers and infected persons. The point being, subways are worse.

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If you take the hand washing and not touching your face, then you're at almost zero risk from using shared bicycles. Even if someone gets some rona on the handlebars, if you don't transfer it to an orifice in your face you won't catch it. It's not gonna re-aerosolize off the handlebars.

"Not touching your face" is not a viable solution for most people. It's subconscious. If anyone could master this kind of self-control within a week, everyone would be an arahat.

If you aren’t aware of this those ML apps that beep when you touch your face are pretty surprising.

Also there’s the whole psychological thing about telling someone not to do something when it was previously largely automatic, making people do it more. Like having an itch or imagining insect bites.

It's not expected to be perfect and immediate. It's about lowering risk as much as feasible and defense in depth.

It's pretty easy to not touch your face when your hands are physically on the handlebars. As long as you are able to wash your hands immediately after getting off the bike, I think you are reasonably safe.

I don't think that's true. People can get a lot better at it in a relatively short period of time. I have.

Face touching is literally unconscious in many cases. It's entirely possible you've been touching your face and not noticing it, but have just become more conscious of the times you attempt to stop yourself from touching your face.

Moving your arms isn't like breathing. It's not some autonomic nervous function.

The handlebars are also out in the sun. I'd think that subjects them to the UV light needed to kill any of the nasty stuff; but I could be wrong.

I read N95 masks were basically useless when walking outside, they only mattered indoors and in confined spaces (like public transit). I’d imagine biking is even less transmission and wearing a mask with that is pretty unrealistic.

It’s hard to find what is right on the internet though.

Useless or pointless?

Pointless waste of a perfectly good mask.

I biked in an N95 in Vancouver during forest fire season in 2018. Not fun, but doable and it definitely helped -- without the mask I felt absolutely awful.

That's for a different situation, though. The smoke particulates are very small and are omnipresent, so a mask definitely helps. Coronavirus, by contrast, is only airborne for a short while, so unless you're close to someone who's infected you're not going to be breathing it in anyway. That's why they're saying the masks have limited effectiveness outside.

Oh, when the GP said it's unrealistic to bike in a mask, I thought they meant it would be too difficult. Maybe they just meant unnecessary, in which case I agree.

Yeah, I'm thinking that's what they must mean. An N95 mask doesn't cut down your breathing that much, and you can simply down-moderate your effort a little bit so that you never hit a pant. It's no gas mask.

When you say it's only airborne for a short while, what exact time range are you speaking about?

https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v...

edit: Sorry, didn't realize that link was subsequently truncated, here is the .pdf: https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v...

There is definitely a higher risk you inhale enough virus progeny indoors than outdoors, yes. We know from the flu that indoors the virus can stay suspended for many hours. Regular talking can project enough virus from an infected person for the air to become sufficiently contaminated, though shedding varies by individual. The more (longer) you breathe that air, the greater your chance of becoming infected. This might also explain why indoors is a greater risk than outdoors, you spend less time in the air that's contaminated, in addition to the greater diffusion/dispersion outdoors, of course.

Are you saying I could breathe in some, conveying a small amount of the virus, and not get infected? That seems to be the opposite of what highly contagious means.

Disclaimer: Not a virologist.

A virus has to achieve viral entry: it has to find a suitable host cell, and introduce its viral material.

https://en.wikipedia.org/wiki/Viral_entry

Whether an aerosol hits your face, or you breathe air with suspended particles containing the virus, the virus has several challenges it needs to overcome (described in the link above). Its success is not guaranteed. An increase in virus particles improves its chance while a decrease improves your chance.

In theory, a single virus particle could achieve its goal.

Do you have a citation for this? I don't want to blindly trust that fomites aren't a major risk.

If true, that changes how I want to get food to my elders. (I've already gotten them several months worth, but I don't see an end to this and would feel safer if they had more runway.)

The CDC does state in one place that inhalation appears to be the primary route: https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmissi...

It says surface -> hands -> mucous membrane "is not thought to be the main way the virus spreads".

But then again, the TTL of the virus on surfaces is still not certain, so, as also noted there "we are still learning how it spreads".

The TTL might be days.

https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v...

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