4 ms·

This is the quote: "All samples came out to be negative for the presence of SARS-CoV-2 genomes with the exception of March 12, 2019, in which both IP2 and IP4 t

by devit 6y ago

This is the quote: "All samples came out to be negative for the presence of SARS-CoV-2 genomes with the exception of March 12, 2019, in which both IP2 and IP4 target assays were positive. This striking finding indicates circulation of the virus in Barcelona long before the report of any COVID-19 case worldwide.". And no discussion of the obvious possibility that they screwed up the testing, any discussion of whether they could repeat the test on another part of the sample or on the 2019 April-August samples they didn't test, or any sort of attempt at a Bayesian probability analysis. Pretty ridiculous and shameful, I'd say.

Ajedi32 6y ago
Pretty much a textbook case of https://xkcd.com/882/ https://xkcd.com/882/ then?
- vikramkr 6y ago
  Yep. Except this time, the people asking about the jelly beans are trying to prove they cure acne, and are also selling jelly beans. "This research was supported in part by the REVEAL project, funded by SUEZ Spain." https://www.suez.es/es-es/seccion-comercial/nuestras-referencias/referencias-comerciales/city-sentinel https://www.suez.es/es-es/seccion-comercial/nuestras-referen...
deleted 6y ago
[deleted]
searine 6y ago
The test from March 2019 wasn't even consistent for a positive result. It found only two of five proteins searched for. Clearly a false positive.
- dmix 6y ago
  Additionally, it was from a 'frozen archival sample' (they tested frozen samples back to 2018 and daily samples from April-May 2020).
im3w1l 6y ago
These kind of oddball claims does seem to belong on such a website in the unlikely case other data points arrive later agreeing with it. But not fit for a broader audience.
- vikramkr 6y ago
  The way they presented their oddball claims definitely don't belong . They didn't present their statistics and sample size, they got what is almost certainly a false positive, and instead of acknowledging any of that, they decided to draw a conclusion and present the idea that the virus was spreading in Barcelona in early 2019. The responsible thing to do is to retest the samples, check for sources of contamination, figure out why only two of the five primers are positive. And, check with colleagues and the literature to find out if the primers have a known false positive rate and if that could be it. And, go ahead and sequence the results of our PCR to see if you can get covid sequences out of it. And if you can't figure out how that result came out after all of that, present that with the clear disclaimer that this doesn't make sense in the context of existing data, detail what you went through to test that finding, and clearly delineate the uncertainty and call for further investigation. This is just sloppy science.
  - hcknwscommenter 6y ago
    "And, go ahead and sequence the results of our PCR to see if you can get covid sequences out of it. " Absolutely. If your hypothesis and/or data flies in the face of all (other) available data, you should leave no stone unturned to prove you are right. Actually showing that the amplified material is in fact COVID sequence would be just one very simple step in doing that. It's been a while, but the cost is about $200 and the time is about 24 hrs to purify and sequence an amplified product? It's quite telling that they didn't bother and/or didn't report the (likely negative result).
    - vikramkr 6y ago
      less than $200 and more than 24 hours if they're outsourcing it to any of the many sequencing providers out there. Still, less than a week total
leliamesteban 6y ago
Thank you for your wise words.
vikramkr 6y ago
The paper is funded by a company with a vested interest in showing the value of wastewater analysis as well, it might not help their cause if they discuss the false positive as a potential problem instead of a great new finding
neuronexmachina 6y ago
I wonder if the sewage includes Barcelona's airport. Hypothetically someone with COVID passing through the airport on a connecting flight could have used the bathroom without transmitting to anyone else in the airport.
- freehunter 6y ago
  Perhaps, but this being March 2019 and knowing how easily transmissible this virus is, there is virtually zero chance it was in the wild as early as March 2019 but didn’t start spreading until nine months later.

by devit 6y ago

Ajedi32 6y ago

Pretty much a textbook case of https://xkcd.com/882/ https://xkcd.com/882/ then?

vikramkr 6y ago
Yep. Except this time, the people asking about the jelly beans are trying to prove they cure acne, and are also selling jelly beans. "This research was supported in part by the REVEAL project, funded by SUEZ Spain." https://www.suez.es/es-es/seccion-comercial/nuestras-referencias/referencias-comerciales/city-sentinel https://www.suez.es/es-es/seccion-comercial/nuestras-referen...

deleted 6y ago

[deleted]

searine 6y ago

The test from March 2019 wasn't even consistent for a positive result. It found only two of five proteins searched for. Clearly a false positive.

dmix 6y ago
Additionally, it was from a 'frozen archival sample' (they tested frozen samples back to 2018 and daily samples from April-May 2020).

im3w1l 6y ago

These kind of oddball claims does seem to belong on such a website in the unlikely case other data points arrive later agreeing with it. But not fit for a broader audience.

vikramkr 6y ago
The way they presented their oddball claims definitely don't belong . They didn't present their statistics and sample size, they got what is almost certainly a false positive, and instead of acknowledging any of that, they decided to draw a conclusion and present the idea that the virus was spreading in Barcelona in early 2019. The responsible thing to do is to retest the samples, check for sources of contamination, figure out why only two of the five primers are positive. And, check with colleagues and the literature to find out if the primers have a known false positive rate and if that could be it. And, go ahead and sequence the results of our PCR to see if you can get covid sequences out of it. And if you can't figure out how that result came out after all of that, present that with the clear disclaimer that this doesn't make sense in the context of existing data, detail what you went through to test that finding, and clearly delineate the uncertainty and call for further investigation. This is just sloppy science.
- hcknwscommenter 6y ago
  "And, go ahead and sequence the results of our PCR to see if you can get covid sequences out of it. " Absolutely. If your hypothesis and/or data flies in the face of all (other) available data, you should leave no stone unturned to prove you are right. Actually showing that the amplified material is in fact COVID sequence would be just one very simple step in doing that. It's been a while, but the cost is about $200 and the time is about 24 hrs to purify and sequence an amplified product? It's quite telling that they didn't bother and/or didn't report the (likely negative result).
  - vikramkr 6y ago
    less than $200 and more than 24 hours if they're outsourcing it to any of the many sequencing providers out there. Still, less than a week total

leliamesteban 6y ago

Thank you for your wise words.

vikramkr 6y ago

The paper is funded by a company with a vested interest in showing the value of wastewater analysis as well, it might not help their cause if they discuss the false positive as a potential problem instead of a great new finding

neuronexmachina 6y ago

I wonder if the sewage includes Barcelona's airport. Hypothetically someone with COVID passing through the airport on a connecting flight could have used the bathroom without transmitting to anyone else in the airport.

freehunter 6y ago
Perhaps, but this being March 2019 and knowing how easily transmissible this virus is, there is virtually zero chance it was in the wild as early as March 2019 but didn’t start spreading until nine months later.