FOMITE THREAD
A very quick thread on fomites.
A very quick thread on fomites.
2/ 1960s 
3/ Staph - blankets had to be covered with staph to transmit
4/ Ditchburn 1971 - RSV on hospital wards. Put up cubicles. They didn't work (they should have, for droplets). Said don't know how got.
5/
6/ "no direct contact"
7/ cubicles did not work.
8/ Hendley 1973 - rhinovirus. Lasts on hands a bit, not recoverable from materials.
9/ Dropped into mouth no infection (so then how do you get infected? Aerosol maybe.
10/ Conclusion, they found can move from fingers elsewhere, but needs to get somewhere that matters. Note that in these trials they typically use large doses on fingers. Someone else can check this paper.
11/ 1975 Dr. Hall did studies of RSV in babies on hospital wards.
12/ Acknowledged in 1975 aerosols, but said less likely because not stable at that humidity (but check those studies, they often result varied numbers, and also did account for constant emission?)
13/ Having disposed of aerosol, authors conclude touch here.
14/ 1975 Reed - about colds.
Noted Tyrell in mid-60s showed aerosol, but later studies "confirmed" droplet. I wonder how. Anyway cites Tyrell and Couch - Couch I posted elsewhere as saying eight diseases airborne n the 1980s.
Says can give colds by aerosol.
Noted Tyrell in mid-60s showed aerosol, but later studies "confirmed" droplet. I wonder how. Anyway cites Tyrell and Couch - Couch I posted elsewhere as saying eight diseases airborne n the 1980s.
Says can give colds by aerosol.
15/ Also says Hendley had proven rhino - Hendley I posted. It said "could" transmit not prove it.
Reed's abstract says can recover from fingers, etc. and people could infect themselves (i.e. told to touch their eyes directly, etc) with "moderately heavy dose".
Reed's abstract says can recover from fingers, etc. and people could infect themselves (i.e. told to touch their eyes directly, etc) with "moderately heavy dose".
16/ Gwaltney 1978 - said recovered rhino from hands, so this is "possible" route. Someone else do the math on how much.
17/ Then interestingly said, we don't get much in the air, but every so often we get a [superspreader] and this might be how rhinovirus transmits.
18/ 1980 Hall Possible fomite of RSV.
Studied how long recovered RSV. Note 20 minutes on hands (/skin?).
Studied how long recovered RSV. Note 20 minutes on hands (/skin?).
19/ Notes all the things that have to line up to make fomite happen.
20/
21/ Doesn't last long on hands.
22/ 1981 Hall and Douglas - Nosocomial RSV.
Had ward use mask, then not use mask. Didn't find much different so concluded droplet and touch.
Had ward use mask, then not use mask. Didn't find much different so concluded droplet and touch.
23/ Here is the timeline.
24/ conclude droplet plus touch
25/ The masks they used block droplet so they concluded droplet.
But look what we learned about masks this year.
But look what we learned about masks this year.
26/ 1982 Bean
"under conditions of heavy environmental contamination, the transmission of influenza virus via fomites may occur"
"under conditions of heavy environmental contamination, the transmission of influenza virus via fomites may occur"
27/ BTW says epi evidence supports that flu is airborne, etc.
This study just suggesting may also be touch component.
This study just suggesting may also be touch component.
28/ Said rhino had a low 50% infectious dose in humans, maybe this accounts for touch in rhino.
29/ Virus lasted on things for a while (it decays though) but not long on hands for flu and RSV.
Even thought flu, with a higher infectious dose (check how this was done, etc. etc.) might still be transmitted by touch.
Even thought flu, with a higher infectious dose (check how this was done, etc. etc.) might still be transmitted by touch.
30/ Flu by air, but may also be touch.
(There are recent studies that model R numbers and suggest flu wouldn't sustain itself with only touch.)
(There are recent studies that model R numbers and suggest flu wouldn't sustain itself with only touch.)
31/ skipping 1982 Gwaltney, 1982 Hall, 1982 Wede, 1983 Hall, 1986 Gala and I'm sure there are others.
1987 Dick - Rhinovirus by aerosol not fomite.
This was the rhinovirus study where they absolutely coated things with secretions and nobody got sick. Posted elsewhere.
1987 Dick - Rhinovirus by aerosol not fomite.
This was the rhinovirus study where they absolutely coated things with secretions and nobody got sick. Posted elsewhere.
32/ Skipping to 2007 Boone for a second, who said very difficult to assess evidence of fomite (of course) because pathway complex.
33/ lab evidence of fomite indirect and circumstantial (yup). That's not to say it doesn't happen but its not rock solid as it is often presented, which is the point of this thread.
34/ Good table of studies.
35/ 2008 Nicas and Best - A Study Quantifying the Hand-to-face contact rate and its potential application to predicting respiratory tract infection
Ran example of flu.
**Concluded
- flu fomite risk seems low.
- Air is efficient.
Ran example of flu.
**Concluded
- flu fomite risk seems low.
- Air is efficient.
36/ elsewhere posted 2017 Xiao, Yuguo Li, Wong, and Hui - did math modelling study of outbreak in HK hospital and it matched air, only to a small degree matched fomite, so perhaps mostly air with small amount fomite.
37/ 2018 Kraay - this is the article that says flu cannot be fomite alone because if run numbers it doesn't sustain transmission.
39/ Done for now. Sorry for brevity & typos.
I would love to see people whose job it is to know these studies go through these studies. I feel like we are just getting regurgitated talking points. Language is not conclusive or determinative, nor are they controlled for aerosol.
I would love to see people whose job it is to know these studies go through these studies. I feel like we are just getting regurgitated talking points. Language is not conclusive or determinative, nor are they controlled for aerosol.
40/ You can pull the author names and review language used and conclusions drawn for yourselves.
Go to ncbi.nlm.nih.gov/search/all/ or Google Scholar.
Search names, etc.
Go to ncbi.nlm.nih.gov/search/all/ or Google Scholar.
Search names, etc.
Meanwhile all evidence of fomite is indirect and circumstantial, but conclusion is "it's an important transmission pathway" (ex pic), meanwhile we have 1500+ superspread events each and every one outside, plus countless "no epidemiological link" and yet some ppl fight vs airborne
Let's walk through this paper that I have in front of me for another reason.
This is a PRO-fomite paper, with a table describing the proof of each virus transmitting by fomite.
Here we go!
This is a PRO-fomite paper, with a table describing the proof of each virus transmitting by fomite.
Here we go!
So, I did not check when they said "proven" what exactly they defined as "proven", but given that elsewhere in the article they (correctly) note that you never really know how a viral infection was transmitted, I'd suggest "proven" may mean "strongly suggested" and not "proven".
Notice how many "not proven", "indirect", "suspected", and "minors" there were up there.
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