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Comment by smileysteve | Hacker News Reader

> Or I see people pulling them down and only pulling them back up when they walk by someone or go into a store

Where a surgical mask is 95% effective at preventing transmission; This is reasonable use.

*If only pulled up before interaction and taken off only after interaction, and treating hands that touched the mask as contaminated after taking it off, you maintain the 30% reduction in contracting the virus.

> or to be just standing around on their front porch/stoop aimlessly

If they're not within 6' of another person; there is nothing inherently bad about being outside.

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> Where a surgical mask is 95% effective at preventing transmission; This is reasonable use.

I think we're still waiting on data on how much virus gets in the air from normal breathing, but it seems plausible that it's not insignificant and may be reduced drastically by you wearing a mask. If you're leaving a cloud of virus in your path, putting on a mask for only the few seconds you're passing someone isn't going to do anything about the cloud of virus you could possibly be leaving in your wake.

> If they're not within 6' of another person; there is nothing inherently bad about being outside.

6ft is a bit of an arbitrary number that's easy to remember, but people are treating it like it's some magic shield. Time spent in proximity presumably plays a factor as well. Walking quickly past someone at 3ft away is probably a lot safer than standing 10ft away from someone and talking for ten minutes. Being outside certainly should help, but in a place with a high concentration of people with the virus I would not consider it a safe activity.

I think there's some really invalid assumptions going on with the reasoning here. I don't have an exact answer, but I can challenge these assumptions.

You don't leave a "virus cloud path" behind you. It just follows the wind in random directions and quickly disperses within a few feet to concentrations that are safe (studies have shown that viral load of initial exposure is a significant factor in disease severity). Below a certain concentration, your immune system will just handle the few viral cells which landed on you.

I would challenge the 3ft vs 10ft thing as actually being a big stretch. I think further research is needed to say anything about that for sure, but keep in mind that beyond some certain distance, probably around 10 feet, distance stops mattering. In some sense, 100 ft is the same as 1000 ft. I would guess the threshold where distance stops mattering is somewhere between 6ft and 10ft, and realistically 10ft should be safe.

> Below a certain concentration, your immune system will just handle the few viral cells which landed on you.

We don't know what a "low viral load" means for infectiousness.

Yes, maybe you fight off the virus successfully after being exposed to a low amount of virus. But perhaps you are infectious for 2 days and infect 2 people.

Who each infect 2 people.

I shouldn't have to explain this here...

2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16,384 32,768 65,536 131,072 262,144 524,288 1,048,576

> We don't know what a "low viral load" means for infectiousness.

One way the phrase is used refers to severity being dependent on initial viral load. That's what I think you're talking about. Someone can have a mild infection or asymptomatic but still be contagious.

What jsharf is referring to is that below the infectious dose, exposure to the virus doesn't necessarily develop into an infection. This idea is explored here: https://erinbromage.wixsite.com/covid19/post/the-risks-know-...

I think it’s a higher amount then we think. Everyone needs to wear a mask.

They are often within 6' of other people, a number which is seemingly arbitrary.

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