Some notes / proposed additions or clarifications:
The #1 hazard noted about copper tape turned out to be cutting yourself on the edge of the tape while applying it (4 independent reports I’m aware of, including myself.) Maybe worth mentioning.
The 24-hour figure from the abstract of the paper about virus survival is misleading (all those numbers reflected the time of the last datapoint they saw virus in, notwithstanding the time of the first virus-free datapoint.) Those numbers (and the whole abstract) were all removed in v2 of the paper (https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v2.full.pdf—you may want to update the link in the post.) So “viable virus could be detected up to 24 hours on cardboard” actually means that it dropped below detectability somewhere in the 24-48h window. The half-life estimation graphs were also made much larger and easier to read in v2; eyeballing the graph, the cardboard number looks to have a median of around 24h, but a distribution that extends outward closer to 36h or 48h. (Although, as you say, this is depending on the concentrations they were using; the half-life, which I believe was reported correctly, is the more important figure.)
On vitamin-D, if you haven’t seen this, someone found a meta-analysis that sort of suggests a benefit even for people with adequate blood levels, if you squint a little bit. (I believe it was a subgroup analysis that showed this, with the subgroup being “taking it daily/weekly, rather than as a bolus”. Which does seem to match how anybody self-supplementing would take it.) https://www.bmj.com/content/356/bmj.i6583
Also, “viable virus could be detected” seems potentially different from “you could get infected from handling it” (in either direction). Your immune system is more robust than the cell culture they use to detect, so many ‘detectable levels of virus’ are still safe, and the detection method requires diluting the contaminated swab, which means that you coming into contact with the undiluted thing might have nonzero risk even when the test can’t detect anything.
But based on my limited understanding of what’s going on, the threshold is within a doubling or two of what’s sensible; not diluting at all should correspond to the 10^0 line on the graph, which their model suggests should be hit within 20-45 (point estimate: 30) hours of when virus is deposited on the box. So unless you’re somehow managing to concentrate the virus, that’s the point at which it couldn’t infect a cell culture without an immune system.
I’m annoyed at the paper authors because I knew to look for this (due to our earlier conversation) and I checked and the phrasing was just that misleading.
Thanks, I am not best pleased about relying on data from a paper that turns out to have been so sloppy. (I guess a rush was understandable under the circumstances, but I think checking all the calculations twice was also arguably imperative under the circumstances! And the misleading abstract was just dumb.)
I’m glad that they ran this experiment, since this is a core uncertainty, and think we should accept that the price of posting drafts is that you have to read them carefully to spot potential errors; having the graph of the raw data a few days earlier was worth having to eyeball the analysis myself to check their numbers.
Yeah, agreed overall. I would not want to discourage literally our only source of direct data on this from doing it again. But ugh, why can’t everyone in the entire world please be like, significantly more careful about everything, all the time? (Preceding sentence is rhetorical and is me making fun of myself for making unreasonable demands.)
Some notes / proposed additions or clarifications:
The #1 hazard noted about copper tape turned out to be cutting yourself on the edge of the tape while applying it (4 independent reports I’m aware of, including myself.) Maybe worth mentioning.
The 24-hour figure from the abstract of the paper about virus survival is misleading (all those numbers reflected the time of the last datapoint they saw virus in, notwithstanding the time of the first virus-free datapoint.) Those numbers (and the whole abstract) were all removed in v2 of the paper (https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v2.full.pdf—you may want to update the link in the post.) So “viable virus could be detected up to 24 hours on cardboard” actually means that it dropped below detectability somewhere in the 24-48h window. The half-life estimation graphs were also made much larger and easier to read in v2; eyeballing the graph, the cardboard number looks to have a median of around 24h, but a distribution that extends outward closer to 36h or 48h. (Although, as you say, this is depending on the concentrations they were using; the half-life, which I believe was reported correctly, is the more important figure.)
On vitamin-D, if you haven’t seen this, someone found a meta-analysis that sort of suggests a benefit even for people with adequate blood levels, if you squint a little bit. (I believe it was a subgroup analysis that showed this, with the subgroup being “taking it daily/weekly, rather than as a bolus”. Which does seem to match how anybody self-supplementing would take it.) https://www.bmj.com/content/356/bmj.i6583
Also, “viable virus could be detected” seems potentially different from “you could get infected from handling it” (in either direction). Your immune system is more robust than the cell culture they use to detect, so many ‘detectable levels of virus’ are still safe, and the detection method requires diluting the contaminated swab, which means that you coming into contact with the undiluted thing might have nonzero risk even when the test can’t detect anything.
But based on my limited understanding of what’s going on, the threshold is within a doubling or two of what’s sensible; not diluting at all should correspond to the 10^0 line on the graph, which their model suggests should be hit within 20-45 (point estimate: 30) hours of when virus is deposited on the box. So unless you’re somehow managing to concentrate the virus, that’s the point at which it couldn’t infect a cell culture without an immune system.
I’m annoyed at the paper authors because I knew to look for this (due to our earlier conversation) and I checked and the phrasing was just that misleading.
Have fixed.
V2 of that paper also corrects the half-life error in v1 discussed by Vaniver here.
The OP has the incorrect values from the first paper. Annoyingly v2 doesn’t give actual numbers but it looks like ~2.5 − 5 hours to me.
Thanks, I am not best pleased about relying on data from a paper that turns out to have been so sloppy. (I guess a rush was understandable under the circumstances, but I think checking all the calculations twice was also arguably imperative under the circumstances! And the misleading abstract was just dumb.)
I’m glad that they ran this experiment, since this is a core uncertainty, and think we should accept that the price of posting drafts is that you have to read them carefully to spot potential errors; having the graph of the raw data a few days earlier was worth having to eyeball the analysis myself to check their numbers.
Yeah, agreed overall. I would not want to discourage literally our only source of direct data on this from doing it again. But ugh, why can’t everyone in the entire world please be like, significantly more careful about everything, all the time? (Preceding sentence is rhetorical and is me making fun of myself for making unreasonable demands.)
Fixed, thank you.