Deb and Ed M
SW MI & Space Coast, FL USA
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For those like my husband who love to watch CNBC - this morning, Jim Cramer (one of the anchors) was on a rant: it seems that he managed to infect co-anchor Carl Quintanilla with Covid. Both guys were triple-vaxxed; Cramer had tested negative shortly before a gathering that both men had attended that required PCR tests; and the next day realized he had Covid and tested positive and that Carl had been infected (and apparently Cramer's wife, too) Basically Cramer's rant was that "nobody knows what's going on" (regarding how fast Omicron spreads) and that testing can't be trusted. And he was pretty much astounded by how fast Omicron spreads. Both men were grateful for their vaccinations and warned that those who are unvaccinated are taking huge risks.
The good news is that both guys are working/broadcasting from their homes, and say that a couple of Tylenol alleviated the discomfort they felt.
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BCSnob
Middletown, MD
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PCR tests generally have very low false positive results (specificity) but can suffer from false negative (sensitivity) tests early in the course of the disease.
Quote:The patients can be categorized as SARS-CoV-2 positive (active case) or SARS-CoV-2 negative based on the outcome of the RT-PCR results. However, this technique does not give information for the patients who have already recovered from the SARS-CoV-2, since the viral load is cleared out of the body after recovery. Equally, the patients who are in the very first days of the viral infection may not respond “positive” with this test due to the inadequate amount of the virus on the swabs.
COVID-19 diagnosis —A review of current methods
Biosens Bioelectron. 2021 Jan 15; 172: 112752.
How many times have we seen news articles where tested negative airline passengers ended up testing positive upon arrival? Isn't this the scenario for several of the first identified Omicron cases outside of South Africa?
It sounds like these on air personalities got a lesson in diagnostic sensitivity and specificity; and in the practicality of mask use even for those vaccinated and/or tested.
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BCSnob
Middletown, MD
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Deb and Ed M wrote:Both guys were triple-vaxxed; Cramer had tested negative shortly before a gathering that both men had attended that required PCR tests; and the next day realized he had Covid and tested positive and that Carl had been infected (and apparently Cramer's wife, too)
I wonder if they quarantined after taking their tests or did they continue their normal routines and have a potential exposure after taking their tests.
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Deb and Ed M
SW MI & Space Coast, FL USA
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BCSnob wrote:Deb and Ed M wrote:Both guys were triple-vaxxed; Cramer had tested negative shortly before a gathering that both men had attended that required PCR tests; and the next day realized he had Covid and tested positive and that Carl had been infected (and apparently Cramer's wife, too)
I wonder if they quarantined after taking their tests or did they continue their normal routines and have a potential exposure after taking their tests.
Cramer's rant was basically (and I question that he actually did a PCR test? Don't those take a few days?)
Cramer: "I took a Covid PCR test and it read negative - and then 3 hours later I attended a gathering (party?) where I infected Carl Quintanilla"
Given that they are celebrities - heaven only knows how many people they interact with in the course of a day. I suspect the answer is "a lot"
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dturm
Lake County, IN
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There appears to be widespread misunderstanding of the limits of testing and how to interpret results.
As Mark said: "It sounds like these on air personalities got a lesson in diagnostic sensitivity and specificity; and in the practicality of mask use even for those vaccinated and/or tested."
Basically, there are very few false positive tests in any of the approved tests either antigen or PCR - meaning that a positive test means you are positive.
All of these tests have some degree of false negative results. Sample retrieval errors (poor swabbing technique), early disease where there is very low viral load and errors in following the actual test steps can result in false negatives.
What this all means is that a positive test result should be considered positive. A negative test might be negative but it would be prudent to continue mitigating behavior - distancing and mask wearing. Serial testing is a way to confirm a negative - two or three consecutive negatives probably mean the negative results are real.
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silversand
Montreal
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Joined: 09/12/2004
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....thanks Mexicowanderer for the link to the RdRp article. Extremely interesting. For those that are involved in vaccine research, why wouldn't Pfizer and Moderna have pursued the RdRp angle when (I am assuming) the vaccine manufacturing industry would have known (?) that the "spike protein" undergoes potentially more rapid (?) mutations?
Beyond the spike article wrote:"The authors discovered that RdRp was “highly conserved,” meaning that the RNA that codes for it is less likely to mutate, within SARS-CoV-2 and other human coronaviruses."
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BCSnob
Middletown, MD
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No one knew the speed at which the sars-cov-2 spike would mutate when the vaccine manufacture’s started developing their vaccines (immediately after the amino acid sequence was published).
There continues to be conserved epitopes (places on the spike where antibodies bind) that are conserved across all sars-cov-2 variants and the other coronaviruses (human and animal).
This quote is from the peer reviewed research article that the linked article reviewed which suggests until this research no one knew this portion of the virus was conserved.
Quote: Cross-reactivity and direct killing of target cells remain underexplored for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific CD8+ T cells. Isolation of T cell receptors (TCRs) and overexpression in allogeneic cells allows for extensive T cell reactivity profiling. We identify SARS-CoV-2 RNA-dependent RNA polymerase (RdRp/NSP12) as highly conserved, likely due to its critical role in the virus life cycle.
Cell Reports
* This post was
edited 12/24/21 08:33am by BCSnob *
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Deb and Ed M
SW MI & Space Coast, FL USA
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Thanks, Mark and Dr Doug, for your ever-valuable insight!
As a side note: I have used the covidactnow.org website to check the rate of new covid cases, simply because using the same source helps see the trends up or down. But since Omicron showed on the scene - there is a HUGE disparity in the numbers for Brevard County, FL as it comes from the County health department (new cases more than doubled in a week, posted on a local social media page today) and covidactnow says "steady". I'm assuming the reporting flows from county health departments, up to the state level; and then goes on to the CDC?
In a state that depends heavily on tourism - I think I know where the numbers get skewed.....
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BCSnob
Middletown, MD
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I’m not sure which is more disconcerting, lagging data for Fla or no data for MD (due to a computer failure at md health dept).
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Deb and Ed M
SW MI & Space Coast, FL USA
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BCSnob wrote:I’m not sure which is more disconcerting, lagging data for Fla or no data for MD (due to a computer failure at md health dept).
I see MD has some seriously-rocketing rates right now (on covidactnow) :-( Maybe their computer burst into flames because it couldn't handle all the numbers ;-)
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