4 ms·

That’s a little too paranoid. Specially now that we know surface transmissions are just anedoctal.

ethbro 6y ago
> Specially now that we know surface transmissions are just anedoctal. Source? Last I saw, there was 48 hr+ viral persistence on plastic and steel. [1] [2] [1] https://www.sciencedirect.com/science/article/pii/S0195670120300463 https://www.sciencedirect.com/science/article/pii/S019567012... [2] https://www.nejm.org/doi/full/10.1056/NEJMc2004973 https://www.nejm.org/doi/full/10.1056/NEJMc2004973
- in_cahoots 6y ago
  The dose makes the poison. Just because you can detect the virus doesn’t mean it is around in quantities that can make you sick. I believe the CDC has updated their guidance to reflect this fact.
  - duaoebg 6y ago
    But it’s not poison it’s a virus. You’re less likely to catch it but if you catch it you get a complete dose.
    - mlyle 6y ago
      This is not exactly correct. A single virus probably can cause infection, but it appears not to be anywhere near a linear correlation between dose and risk. And severity can be tied to initial dose, too. This is one interesting thing about masks: they may do more to improve prognosis than reduce infection. Further, when we're talking about ... e.g virus on cardboard... the way you do the test is after the droplet on the cardboard has dried, you use a buffer to dissolve the virus back out of the cardboard and see if you can grow it in culture. This may recover virus in cases where there's absolutely no chance for casual contact to get it out.
    - weaksauce 6y ago
      there is such a thing as minimal infective dose. they do not know what the minimal infective dose is yet though. there is no you get one virus particle and now you have the virus... rather, you have a worked out average dose of the virus particles that if you gave a population of people that much of the virus 50% of them would become ill.
wittyreference 6y ago
We know no such thing. There was a recent letter to the editor that claimed that the virion concentrations used in the surface contamination studies were orders of magnitude too high - but itself could not cite any study offering strong evidence of the correct concentration of virions per droplet. It’s on the basis of this letter that a recent Atlantic article was written, and the meme was born that we’ve been far too cautious about surface contamination. This remains a known unknown, and asserting a conclusion in either direction at this time is a victory of emotion over knowledge.
- Camillo 6y ago
  Informed people have been downgrading the importance of surface transmission for weeks, if not months. It didn't start with that letter or with that article.
  - wittyreference 6y ago
    You mean like the CDC publishing a statement that they are considering the likelihood of surface transmission 'low', in the same time that there were no new studies to support a change, they cited no research or reasoning, but we had multiple independent government sources contemporaneously complain that their monitoring efforts were being interfered with to downplay the seriousness of the outbreak? I somehow failed to take that statement to heart. There have been repeated claims that we haven't detected surface transmission - but ruling out fomite transmission in a droplet-transmitted disease such as this is a joke. The best you can do is rule out fomite transmission after long periods of time. Which is fine for something like "do I have to worry about my amazon package's contents, which hasn't been touched by human hands in at least 24 hours?" but not in a scenario like the OP's, where a high traffic area like a store means you can have surface contact within minutes of contamination. The most conservative papers I've seen regarding surface transmission consider the safe period 'after a couple of hours', which is not the threat model of OP's post.
celticninja 6y ago
Do we? There seems to be plenty of research that shows covid19 can survive on hard surfaces for >24 hours. I have not seen anything that says transmission by this method is not possible or even that it is just anecdotal.

> Specially now that we know surface transmissions are just anedoctal. Source? Last I saw, there was 48 hr+ viral persistence on plastic and steel. [1] [2] [1] https://www.sciencedirect.com/science/article/pii/S0195670120300463 https://www.sciencedirect.com/science/article/pii/S019567012... [2] https://www.nejm.org/doi/full/10.1056/NEJMc2004973 https://www.nejm.org/doi/full/10.1056/NEJMc2004973

in_cahoots 6y ago
The dose makes the poison. Just because you can detect the virus doesn’t mean it is around in quantities that can make you sick. I believe the CDC has updated their guidance to reflect this fact.
- duaoebg 6y ago
  But it’s not poison it’s a virus. You’re less likely to catch it but if you catch it you get a complete dose.
  - mlyle 6y ago
    This is not exactly correct. A single virus probably can cause infection, but it appears not to be anywhere near a linear correlation between dose and risk. And severity can be tied to initial dose, too. This is one interesting thing about masks: they may do more to improve prognosis than reduce infection. Further, when we're talking about ... e.g virus on cardboard... the way you do the test is after the droplet on the cardboard has dried, you use a buffer to dissolve the virus back out of the cardboard and see if you can grow it in culture. This may recover virus in cases where there's absolutely no chance for casual contact to get it out.
  - weaksauce 6y ago
    there is such a thing as minimal infective dose. they do not know what the minimal infective dose is yet though. there is no you get one virus particle and now you have the virus... rather, you have a worked out average dose of the virus particles that if you gave a population of people that much of the virus 50% of them would become ill.

wittyreference 6y ago

We know no such thing. There was a recent letter to the editor that claimed that the virion concentrations used in the surface contamination studies were orders of magnitude too high - but itself could not cite any study offering strong evidence of the correct concentration of virions per droplet. It’s on the basis of this letter that a recent Atlantic article was written, and the meme was born that we’ve been far too cautious about surface contamination. This remains a known unknown, and asserting a conclusion in either direction at this time is a victory of emotion over knowledge.

Camillo 6y ago
Informed people have been downgrading the importance of surface transmission for weeks, if not months. It didn't start with that letter or with that article.
- wittyreference 6y ago
  You mean like the CDC publishing a statement that they are considering the likelihood of surface transmission 'low', in the same time that there were no new studies to support a change, they cited no research or reasoning, but we had multiple independent government sources contemporaneously complain that their monitoring efforts were being interfered with to downplay the seriousness of the outbreak? I somehow failed to take that statement to heart. There have been repeated claims that we haven't detected surface transmission - but ruling out fomite transmission in a droplet-transmitted disease such as this is a joke. The best you can do is rule out fomite transmission after long periods of time. Which is fine for something like "do I have to worry about my amazon package's contents, which hasn't been touched by human hands in at least 24 hours?" but not in a scenario like the OP's, where a high traffic area like a store means you can have surface contact within minutes of contamination. The most conservative papers I've seen regarding surface transmission consider the safe period 'after a couple of hours', which is not the threat model of OP's post.

celticninja 6y ago

Do we? There seems to be plenty of research that shows covid19 can survive on hard surfaces for >24 hours. I have not seen anything that says transmission by this method is not possible or even that it is just anecdotal.