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Thread—On the paper published by Peter de Man recently, presumably showing evidence for transmission of SARS-CoV-2 by aerosols in a Dutch nursing home ("Tweemaster" in the city of Maassluis).Here's why I think it is a controversial (and misleading) paper.
(0/28)
First of all, here's the link to De Man's paper.
"Outbreak of COVID-19 in a nursing home associated with aerosol transmission as a result of inadequate ventilation"
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1270/5898577
Effectively just 2 A4 pages + half page appendix + graph.
(2/28)
"Outbreak of COVID-19 in a nursing home associated with aerosol transmission as a result of inadequate ventilation"
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1270/5898577
Effectively just 2 A4 pages + half page appendix + graph.
(2/28)
And this is the thread by @DrEricDing on it, going 'viral'...
https://twitter.com/DrEricDing/status/1300777854603591680
... hence the reason for this thread to be written in English too.
Shortcut: skip to (19/28) for the "counter research" by Dutch CDC (RIVM) & public health services (GGD).
(3/28)
https://twitter.com/DrEricDing/status/1300777854603591680
... hence the reason for this thread to be written in English too.
Shortcut: skip to (19/28) for the "counter research" by Dutch CDC (RIVM) & public health services (GGD).
(3/28)
Those who haven't followed Dutch news recently, there are A LOT of 'drama' leading up to this which is relevant to the context to this very small paper.
So, let's go back, what happened? Sorry for the noise on media drama, but relevant here.
(4/28)
So, let's go back, what happened? Sorry for the noise on media drama, but relevant here.
(4/28)
Rewind!
Late June, the nursing home was in the news with an outbreak. Dutch article by local media.
https://wos.nl/nieuws/artikel/17-bewoners-en-8-medewerkers-tweemaster-nu-besmet-met-corona
(5/28)
Late June, the nursing home was in the news with an outbreak. Dutch article by local media.
https://wos.nl/nieuws/artikel/17-bewoners-en-8-medewerkers-tweemaster-nu-besmet-met-corona
(5/28)
It had to lock down and the public health services (GGD) started an investigation. It was able to reopen again July 7. Dutch article on this, in other local media.
https://www.rijnmond.nl/nieuws/196925/De-Tweemaster-in-Maassluis-vanaf-dinsdag-weer-grotendeels-open-voor-bezoek
(6/28)
https://www.rijnmond.nl/nieuws/196925/De-Tweemaster-in-Maassluis-vanaf-dinsdag-weer-grotendeels-open-voor-bezoek
(6/28)
A colleague of Peter de Man, working in the same hospital, shares his opinion early August and report to the media that the Dutch CDC (RIVM) is holding back on some groundbreaking results. Dutch article.
https://twitter.com/EenVandaag/status/1291012188921110529
(7/28)
https://twitter.com/EenVandaag/status/1291012188921110529
(7/28)
Before we fully knew the arguments of the Dutch CDC (RIVM) and public health services (GGD) on this, already the arguments by Peter de Man were causing some doubt...
(8/28)
(8/28)
Leading Dutch newspaper Volkskrant published a misleading article quoting an "expert" completely misunderstanding the meaning of Ct values in PCR tests, resulting in the misinformation that the virus was found "in high levels".
https://www.volkskrant.nl/nieuws-achtergrond/vertrouwelijk-rivm-rapport-ventilatiesysteem-verspreidde-virus-in-verpleeghuis~bdc4943d/
(9/28)
https://www.volkskrant.nl/nieuws-achtergrond/vertrouwelijk-rivm-rapport-ventilatiesysteem-verspreidde-virus-in-verpleeghuis~bdc4943d/
(9/28)
The ventilation system's samples were showing a "very high Ct value", but this was explained as argument in having clear evidence for transmission.
Higher Ct values (cycle treshold) mean lower amount of virus. Beginner's mistake, really.
https://twitter.com/mkeulemans/status/1291481627235934208
(10/28)
Higher Ct values (cycle treshold) mean lower amount of virus. Beginner's mistake, really.
https://twitter.com/mkeulemans/status/1291481627235934208
(10/28)
In the Dutch talk show Op1, Peter de Man talked about his research and made serious accusations against the Dutch CDC (RIVM) and the public health services (GGD) for pressuring him to keep silent about his findings and opinion. Video in Dutch.
https://twitter.com/op1npo/status/1293288467783397389
(11/28)
https://twitter.com/op1npo/status/1293288467783397389
(11/28)
His technical explanation for the high Ct value (extremely low amount of virus) was that the samples were taken multiple days after the people living there were tested positive. Valid point, makes sense. Does not prove the opposite (his main point), however.
(12/28)
(12/28)
Just before his appearance in the Op1 talk show, the GGD and RIVM published their initial findings that it was unlikely to be caused by poor ventilation and that they have a different view on the causes for the outbreak.
https://www.ggdrotterdamrijnmond.nl/nieuws/conclusies-tweemaster/
(13/28)
https://www.ggdrotterdamrijnmond.nl/nieuws/conclusies-tweemaster/
(13/28)
That timing was considered very controversial and was feeding a lot of conspiracy thinking about a truth that's being hidden.
I agree that at the time, this was a very bad move to keep things to themselves, and only caused more harm and confusion in the media.
(14/28)
I agree that at the time, this was a very bad move to keep things to themselves, and only caused more harm and confusion in the media.
(14/28)
The initial conclusions shared were interesting already, however. Two takes.
1) health care workers have been taking breaks together closely (insufficient distance, no masks used) and may be a cause of transmission as well.
(15/28)
1) health care workers have been taking breaks together closely (insufficient distance, no masks used) and may be a cause of transmission as well.
(15/28)
