Though also hard to square that with dry winter conditions being prime cold and flu season.
Yeah, that’s an interesting consideration which came up in discussion with someone yesterday. Another possibility is that people congregate indoors more during wintertime, but I haven’t looked into that specific question. (It wouldn’t surprise me if someone had looked into it during COVID.)
I could also imagine it being the case that viruses are much less likely to be transferred from one patch of dry skin to another patch of dry skin via normal contact, than they are to be picked up by whatever mechanisms are used in various studies to check for the “presence” of viruses on surfaces. In several cases, this was approximately “dip fingers into some kind of liquid solution, then culture whatever was picked up in that solution”.
Unfortunately, the disinfectant results from Gwaltney & Hendley, 1982 point in the opposite direction:
Spraying of contaminated tiles with a commercially available phenol/alcohol disinfectant reduced (p = 0.003) the rate of recovery of virus from the tiles from 42% (20/47) to 8% (2/26). Similarly, the rate of detection of virus on fingers touching the tiles was reduced (p = 0.001) from 61% (28/46) with unsprayed tiles to 21% (11/53) with sprayed tiles. Fifty-six per cent (9/16) of the recipients exposed on three consecutive days to untreated tiles became infected while 35% (7/20) touching only sprayed tiles became infected with rhinovirus (p = 0.3).
The reduction in lab detection of viruses from the plastic tiles after being sprayed with a disinfectant (and then left to dry for 10 minutes) was much larger than the reduction in people getting sick after rubbing their fingers on the disinfected tiles (vs. non-disinfected tiles), and then rubbing their eyes/nose.
I expect this sort of thing to be quite sensitive to object-level details, and the sample sizes here aren’t huge.
Huh, more questions than answers there. Not a biologist but I’ve got to think there’s an easier way to study the surface transmission part than with live virus. If we’re assuming that: the virus is basically inert on surfaces and can’t move or divide or do much of note; transmission is just a function of how much intact virus makes it to the recipients tissues; then that should let us factor out studying how a ball of proteins about that size move through the environment from actually infecting people. And there’s got to be an easier way to test—add a marker to something that’s still a decent virus analog, like splice in a florescent protein or something that you can just see at a glance “how much”, but it’s still a protein that can denature at a similar rate. I’ve heard of demos like that using glitter or chemicals to show surface transmission, but that doesn’t capture degradation and has too many other differences.
The degree to which the virus is potentially degrading in the environment just sitting there is also a big confounder—how much did it degrade while waiting for the test vs before you took the sample? So something that let’s you test instantly seems worth a little extra fuss.
Yeah, that’s an interesting consideration which came up in discussion with someone yesterday. Another possibility is that people congregate indoors more during wintertime, but I haven’t looked into that specific question. (It wouldn’t surprise me if someone had looked into it during COVID.)
I could also imagine it being the case that viruses are much less likely to be transferred from one patch of dry skin to another patch of dry skin via normal contact, than they are to be picked up by whatever mechanisms are used in various studies to check for the “presence” of viruses on surfaces. In several cases, this was approximately “dip fingers into some kind of liquid solution, then culture whatever was picked up in that solution”.
Unfortunately, the disinfectant results from Gwaltney & Hendley, 1982 point in the opposite direction:
The reduction in lab detection of viruses from the plastic tiles after being sprayed with a disinfectant (and then left to dry for 10 minutes) was much larger than the reduction in people getting sick after rubbing their fingers on the disinfected tiles (vs. non-disinfected tiles), and then rubbing their eyes/nose.
I expect this sort of thing to be quite sensitive to object-level details, and the sample sizes here aren’t huge.
Huh, more questions than answers there. Not a biologist but I’ve got to think there’s an easier way to study the surface transmission part than with live virus. If we’re assuming that: the virus is basically inert on surfaces and can’t move or divide or do much of note; transmission is just a function of how much intact virus makes it to the recipients tissues; then that should let us factor out studying how a ball of proteins about that size move through the environment from actually infecting people. And there’s got to be an easier way to test—add a marker to something that’s still a decent virus analog, like splice in a florescent protein or something that you can just see at a glance “how much”, but it’s still a protein that can denature at a similar rate. I’ve heard of demos like that using glitter or chemicals to show surface transmission, but that doesn’t capture degradation and has too many other differences.
The degree to which the virus is potentially degrading in the environment just sitting there is also a big confounder—how much did it degrade while waiting for the test vs before you took the sample? So something that let’s you test instantly seems worth a little extra fuss.