What Is A Covid-19 Case?

Autor: Dr. Sam Bailey.

Source. 

Yeah that's right. The breaks are off and I’m talking about COVID again.
Who would have thought we'd be asking
this question at this stage of the global COVID-19 situation?
In today's video I’m going to explore
some often overlooked fundamental issues. It can be surprising when we scratch beneath the surface and go back to some basic scientific
principles. Minor misunderstandings of these
principles can magnify dramatically and manifest in all sorts of unexpected ways.
I've got a few interesting recent developments to discuss too so make sure you watch till the end.
First of all we need to be clear that a case is not the same as a clinical diagnosis.
Let's go to the medical dictionary to get these definitions right. 
In general a "clinical diagnosis refers to a diagnosis based on signs, symptoms and laboratory findings during life."
Now the definition of a case can mean instance of disease in the narrower clinical sense but in the wider epidemiological sense it simply means "the standard criteria for categorizing an individual as a case."
While defining cases can certainly help
us understand and manage disease outbreaks, we need to be careful when applying case definitions. For example if the criteria is too broad or non-specific this can result in too much meaningless data. So how do we make a clinical diagnosis of COVID-19? If we search around the WHO website, even though it talks about symptoms and testing, it doesn't appear that there are any formal diagnostic criteria for the disease. Although they do state "a molecular test is used to confirm an active infection" and "polymerase chain reaction (PCR) is the most commonly used molecular test.
You can check out my video here to see the possible problems with using PCR tests for diagnostic purposes.
And what do the ever trustworthy cochrane group have to say?
Back in july they performed a literature review with regards to signs and symptoms used to diagnose COVID-19 and concluded the following:
"Based on currently available data neither absence nor presence of signs or symptoms are accurate enough to rule in or rule out disease."
It's now almost a year into the situation and as far as I am aware. We are not much further ahead in this area.
In summary we don't seem to have standardized clinical diagnostic criteria for COVID-19 - outside of the PCR test signs - symptoms and other investigations may be recorded, but they are not required. 
Virus isolation is similarly not required. What about a case definition for COVID-19?
The WHO website states that a confirmed COVID-19 case is "a person with laboratory confirmation of COVID-19 infection, irrespective of clinical signs and symptoms.""
Dr Claus Köhline pointed out the problem with defining cases this way in my recent interview with him. He described it as a PCR pandemic. Additionally a (!!!) case (!!!) is technically (!!!) whatever a health authority says it is (!!!) so it can change over time and make comparisons of data meaningless. (!!!!!) Useful conclusions can only be drawn when the case definition is consistent (!!!!) - and we take into account what it is - we
are actually defining ... We are in a strange
situation, where in most instances a "case" can be determined solely by a positive PCR test and the clinical diagnosis is also
solely determined by a positive PCR test. You will notice that the requirement of - disease - is conspicuous by its absence. This is still technically valid under the definition of - case - keeping in mind that this can be loosely defined; but in this setting it should be made clear that the COVID cases refer only to people that had a positive PCR
test - nothing more than that it. And introduces significant issues when a standalone PCR test - is used - for the clinical diagnosis of COVID-19 ... as it becomes disconnected from the concept of disease. 
But wait! ... There's more! It is typical in medical and health matters to have some idea of the false positive rate for a test. For example a pregnancy test would be considered a false positive if there was no actual pregnancy in the setting of a positive pregnancy test.
But the way the COVID-19 PCR tests are being used in the population - by definition - there can be no concept of false positives, and as I've discussed in a previous video I’m not talking about false positive rates reported for SARS-CoV-2 PCR tests from a single isolate in a laboratory setting... I’m talking about using the PCR tests in the population at large. 
Just to throw another spanner in the works I'd like to give the microphone to our old friend dr Fauci. Now unlike some of us PCR skeptics dr Fauci believes a PCR test is a valid way to confirm COVID-19. But in this interview he admits that the concept of a positive test is not that simple:
"Again a good question. And what is now sort of evolving into a bit of a standard that if you get a cycle threshold of 35 or more
that the chances of it being replication
competent are minuscule... So that if somebody and you know we do we have patience and it's very frustrating for the patients as well as for the physicians: somebody comes in and they repeat their PCR and it's like
37 cycle threshold. But you never - if you
almost never - can culture virus from a 37 threshold cycle. So I think if somebody does come in with 37, 38, even 36 you got to say - you know - it's just - it's just dead nucleotides, period." 
The New York times subsequently reported that the limit for most COVID-19 PCR tests in the US is 37 to 40 cycles. In Europe labs also work with up to 40 cycles. Here in New Zealand an official information act request has revealed that labs are typically running
- 40 cycles.
Didn't even Dr Fauci just say those cycle thresholds are too high that is echoed by the times article which reports Harvard  epidemiologist dr Michael Mina is saying he "would set the figure at 30, or even less."
Indeed even less was suggested by a clinical infectious disease journal study (J. Bullard et al, 22 May 2020, p.p.):
"These results demonstrate that infectivity (...) is significantly reduced. When RT-PCR Ct values are greater than 24. For every one unit increase in Ct - the odds ratio for infectivity decreased by 32% (!!!!!)."
The difference between 24 cycles and 30 cycles let alone 40 cycles is enormous - it's literally exponential. 
* * *
Even if the critics dismiss all of the concerns we raised with case definition and clinical diagnosis criteria and maintain a PCR test as the only requirement to detect COVID-19. Hasn't a crucial variable being introduced regarding cycle numbers? 
If that's the case surely the PCR proponents have been carefully collating cycle data.
It seems - no ... The Times article goes on to state officials at some state labs said the CDC had not asked them to note threshold
values or to share them with contact tracing
organizations. How did we get into this mess with PCR cycle thresholds? The article goes on to state the food and drug administration said in an email statement that it does not specify the cycle threshold ranges used to determine who is positive and that commercial manufacturers and laboratories set their own ... You can draw your own conclusions there ... In fact the original Corman Drosten COVID PCR test first published in january 2020 has led to much of the confusion because it was woolly around definitions and standard operating procedures. With regards to this paper, on november 26 a consortium of health professionals and scientists sent a "Retraction request letter to Eurosurveillance " (Euro-surveillance). They documented numerous problems with the Drosten paper. It is possible that some of the technical issues relating to the laboratory techniques, may be resolved but to me - they identified the following key issues:
1) The number of PCR cycles to be used was not specified and there was no definition of what defines a positive or negative result. 
2) The PCR test cannot discriminate between the whole virus in viral fragments. 
3) A positive test cannot be equated to infection with a virus.
i.e it has no clinical relevance. 
Corman and Josten failed to disclose their affiliations with the commercial test laboratory - Labour Berlin - which is involved in PCR testing. In any case it seems that when it comes to COVID-19 we still don't have many sound principles behind either case definition or clinical diagnosis. 
And is this a major problem?
Yeah it's gonna be a problem. There's gonna be a problem for them.
I was having a conversation about this recently with Dr Simon Thornley public
health physician at the university of Auckland. Dr Thornley directed me to an article in the BMJ discussing the implications of how we classify conditions. I'd encourage you to have a look at the article which I've linked in the description it explains the different ways in which over-diagnosis can occur. Especially by over-detection or over-definition. The authors state that while the forms of over-diagnosis differ, the consequences are the same. Diagnoses that ultimately cause more harm than benefit.
Is there any hope that the COVID situation is going to be resolved anytime soon? That I cannot say that there have been some fascinating developments recently. Four
German tourists who were illegally quarantined in portugal on the basis of a COVID-19 PCR test have won a Lima court case. The judges in the Lisbon court of appeal delivered some decisive rulings including:
"In view of current scientific evidence this test shows itself to be unable to determine beyond reasonable doubt that such positivity corresponds in fact to the infection of a person by the SARS-CoV-2 virus." And "the test's reliability depend on the number of cycles used."
It's sad that we are needing court cases to point out the shortfalls of the PCR test that perhaps it's one of the only ways forward when (!!!!) politicians and health institutions seem unable to follow the science (!!!!)

Keep the conversation going in the comments section and as always. I’m grateful to be made aware of new information you may discover in your own research to help sustain my channel in this time of censorship. Please support my work on subscribe star link is in the description.