These were the old criteria for a confirmed or probable case:
"Confirmed: A clinically compatible illness that is laboratory confirmed by isolation of B. pertussis from a pernasal swab, or epidemiologically linked to a confirmed case.
Probable: Cough lasting longer than two weeks and one or more of the following ...":
After 31 May 2012, the Ministry of Health added new criteria in red:
"Confirmed: A clinically compatible illness that is laboratory confirmed by isolation of B. pertussis or detection of B. pertussis nucleic acid, preferably from a nasopharyngeal swab, or is epidemiologically linked to a confirmed case.
Probable: A clinically compatible illness with a high B. pertussis IgA test or a significant increase in antibody levels between paired sera at the same laboratory..."
The routine use of this new PCR test in New Zealand to detect DNA (nucleic acid) from whooping cough bacteria, is presumably, - primarily - to justify jumping in really quick with the antibiotic Azithromycin.
The introduction of two antibody tests one month apart, (which supposedly proves that an active infection has occured) are presumably, to "confirm" that the case was whooping cough, not something else which can mimic whooping cough. But there could be other "consequences" of these two tests which might be "intended" consequences.
The "old" diagnostic method was the culture method, where the bacteria from a swab is smeared onto a culture medium in a "plate", and put away for a few days to grow. Then bacteria are looked for under a microscope. But while the older test is much cheaper to do, it is labour intensive, requires the bacteria to still be alive before being put onto culture medium, and the results take a few days. The test can also be wrecked, if samples aren't taken properly, stored properly etc.
The newer Polymerase Chain Reaction test is a fast geeky genetic test, which looks for bits of bacterial DNA. Unlike the culture test, the PCR test doesn't require LIVE bacteria to be present, and is easy to do in comparison with the culture test, but is more expensive.
However, the newer PCR test has quite a few problems.
The first is, that the test can create a false positive diagnosis of "pertussis" in people with supposedly classic whooping cough symptoms, when those symptoms are not caused by the whooping cough bacteria at all.
The second is that PCR testing is easily contaminated.
Here is an example of how, over several months during 2006 in Dartmouth University USA false positive whooping cough PCR tests, completely misled infectious disease experts. I've highlighted and emphasized the coloured extract below:
"For two weeks starting in mid-April last year,
she coughed, seemingly nonstop, followed by another week when she coughed
sporadically, annoying, she said, everyone who worked with her.
Before long, Dr. Kathryn Kirkland, an infectious disease specialist at Dartmouth, had a chilling thought: Could she be seeing the start of a whooping cough epidemic? By late April, other health care workers at the hospital were coughing, and severe, intractable coughing is a whooping cough hallmark. And if it was whooping cough, the epidemic had to be contained immediately because the disease could be deadly to babies in the hospital and could lead to pneumonia in the frail and vulnerable adult patients there.
It was the start of a bizarre episode at the medical center: the story of the epidemic that wasn't.
For months, nearly everyone involved thought the medical center had had a huge whooping cough outbreak, with extensive ramifications. Nearly 1,000 health care workers at the hospital in Lebanon, N.H., were given a preliminary test and furloughed from work until their results were in; 142 people, including Dr. Herndon, were told they appeared to have the disease; and thousands were given antibiotics and a vaccine for protection. Hospital beds were taken out of commission, including some in intensive care.
Then, about eight months later, health care workers were dumbfounded to receive an e-mail message from the hospital administration informing them that the whole thing was a false alarm.
Not a single case of whooping cough was confirmed with the definitive test, growing the bacterium, Bordetella pertussis, in the laboratory. Instead, it appears the health care workers probably were afflicted with ordinary respiratory diseases like the common cold.
...At Dartmouth the decision was to use a test, P.C.R., for polymerase chain reaction...
...Many of the new molecular tests are quick but technically demanding, and each laboratory may do them in its own way. These tests, called ''home brews,'' are not commercially available, and there are no good estimates of their error rates. But their very sensitivity makes false positives likely, and when hundreds or thousands of people are tested, as occurred at Dartmouth, false positives can make it seem like there is an epidemic.
....Yet, epidemiologists say, one of the most troubling aspects of the pseudo-epidemic is that all the decisions seemed so sensible at the time. "
No doubt the New Zealand scientists also think their decision to change the diagnostic criteria is very sensible. But... is it? If so, for whom and why?
As New York Times showed... when the university decided to CHECK the PCR results with the longer laborious culture method tests, they found that.... oops... what every single clinician THOUGHT was whooping cough based on the symptoms and a positive PCR test.... was actually ... something else.
Which also calls into question the ability of infectious disease "experts" to diagnose whooping cough on clinical symptoms, in the first place. Dartmouth University did NOT however use a pertussis IgA antibody test to confirm the PCR test results. .
The Dartmouth experience was only one of several examples which showed the CDC, that the PCR test for whooping cough could incorrectly inflate case numbers with false positives.
That is why this diagnostic change in New Zealand is so puzzling.
1) : "...only patients with signs and symptoms consistent with pertussis should be tested by PCR to confirm the diagnosis.
Which is fine, so long as that is the ONLY situation in which the PCR is used.
CDC goes on to say: Testing asymptomatic persons should be avoided as it increases the likelihood of obtaining falsely-positive results. Asymptomatic close contacts of confirmed cases should not be tested and testing of contacts should not be used for post-exposure prophylaxis decisions.
What does the above paragraph mean?
It means that lots of people without any symptoms (asymptomatic) who will not get any disease, will have whooping cough bacteria in their throats, because during an outbreak over 50% of people carry it. If they are swabbed, the over zealous doctor might then want to treat them with antibiotics supposedly to prevent infection (post-exposure prophylaxis) . So CDC is saying ONLY test and treat people with proven disease.
Will the NZ doctors realise there is a good reason not to test anyone other than a person with classical whooping cough symptoms? Might they decide to test all contacts too, when they shouldn't?
There appears to be another omission from the New Zealand
information, which is that:
2) The PCR test is hugely susceptible to contamination. Again, CDC says:
"Avoiding Contamination of Clinical Specimens with Pertussis DNA
Some pertussis vaccines have been found to contain PCR-detectable B. pertussis DNA. Environmental sampling has identified B. pertussis DNA from these vaccines in clinic environments. While the presence of this DNA in the vaccines does not impact the safety or immunogenicity of these vaccines, accidental transfer of the DNA from environmental surfaces to a clinical specimen can result in specimen contamination and falsely-positive results. If health care professionals adhere to good practices, there is no need to switch vaccines.
However, while contamination from a DPT vaccine in a doctor's practice or hospital should be unlikely if staff follow protocol - the far more likely source of sample contamination would be bacterial DNA in the practice itself, or in the air of the laboratory concerned. Here are two hypothetical examples of environmental contamination in a doctor's surgery:
A suspected case is swabbed in a doctor's surgery not long after an actual case presents. That case may have had a nasopharygeal swab taken which is WAY up the back of the nose which won't be cleared out by nose blowing. They can't do a throat swab, because when you swallow, you swallow bacteria down to the stomach and the bacterial concentrations in the mouth are minimal. The ONLY decent place to collect whooping cough bacteria from, is the nasopharyngeal crypt. How "uncomfortable" the test is, is dependant on the skill of the tester.
Just the presence of a whooping cough patient, can result in whooping cough bacterial DNA in the air, lying inactive on surfaces in the doctor's reception rooms, office, and the swab testing facilities. These unseen bacterial contaminants from previous patients can be accidentally transferred to the naso-pharangeal swab, resulting in the suspected case (- which might not be pertussis at all -) being told that they have whooping cough. Immediately, every contact of the suspected case, is prescribed Azithromycin on the basis of a contaminated false positive test result, and/or vaccinated, as in the Dartmouth situation.
OR - a staff member handing the whooping cough swab either in the doctor's practice or the lab, could be an asymptomatic carrier of the whooping cough bacteria with no symptoms and anything they exhale into the air, could contaminate any sample during that time frame. As is so often the case with adults, whooping cough is rarely suspected or diagnosed.
So the nasopharyngeal swab could become contaminated by whooping cough in different ways, by DNA from air, surfaces or hands. With the PCR test, the bacteria doesn't have to be alive or infectious to be identified. The bacterial DNA just has to be "there".
So .. "Have doctors/nurses been told about increased false
positives and varied routes of sample contamination???"
One tutorial on PCR says: "PCR-based tests are also extremely sensitive to contaminating DNA at the crime scene and within the test laboratory. During PCR, contaminants may be amplified up to a billion times their original concentration. Contamination can influence PCR results, particularly in the absence of proper handling techniques and proper controls for contamination."
Put it this way… if a forensic sample was taken the same way as as a PCR test taken in a doctor's surgery, and couriered, opened, and treated the same manner, that PCR sample would likely be inadmissible in court as evidence, due to the potential for contamination, and resulting miscarriage of justice…
Given that the PCR test grossly OVER-estimates case numbers and as
states: "should not be used to diagnose outbreaks of the
disease", who benefits from adding these two tests into the
New Zealand guidelines?
Supposedly, babies and the sick. The result of the quick PCR test will be used to justify "immediate treatment and prevention" strategy, consisting of napalming everyone in sight with "free" Azithromycin (supposedly to prevent spread) while at the same time, giving the same people vaccines, and "cocooning" family, friends, schoolmates with an extra booster of whooping cough vaccine (plus a few other vaccines in the same syringe) all on the false premise that it will be of benefit. Even Australia has recently abandoned cocoooning when their research showed it was not evidence based and did not work.
Is the new changes in diagnostic methods, scientifically and financially
acceptable, in light of false positives and contamination issues?
The inclusion of two sequential antibody tests (a month apart) could clarify the situation. All people whose nasopharyngeal swabs are sent for PCR testing, should have the first antibody blood test done at the same time as the nasopharygeal swab. This first antibody test provides the "baseline" measurement, and the second blood test taken a month later, should show at least a four fold rise in whooping cough antibody levels - if the person has had whooping cough.
If a PCR test result comes back positive, BUT the second antibody test one month later showed no rise in antibodies, then the authorities should discard the PCR result, because the lack of antibody rise, proves that the PCR was a contaminated false positive incorrect result.
The problem though - is that during that month between the first and second antibody test, vaccines, and Azythromycin will be used on that person and all their contacts like tapwater, because the PCR test result falsely said "this person has whooping cough". And most patients will never know that the PCR test was false, because they won't be told.
If MOST of the PCR tests came back positive, and MOST of the second antibody tests also came back negative (no rise), then we would know that EITHER the whole expensive diagnostic and treatment protocol was a huge waste of taxpayers time and money, OR that the antibiotics used between the two tests, prevented any rise in body antibodies. Which of the two reasons is the best, is impossible to assess from the limited medical literature on the topid. It it worth the shotgun use of antibiotics, which don't help the clinical disease, but do increas community bacterial resistance, and adverse reactions, and gut damage from the antibiotics?
I suspect that the PCR test AND antibody tests will NOT be used
together. What ESR doesn't know, can't be justified or confessed.
As you have seen from the medical article in the pertussis blogs collected together in the whooping cough resource series, there is always significant subclinical boosting of immunity without clinical disease. That known fact has always been a major part of whooping cough epidemiology.
Immunity conferred by subclinical boosting from community bacterial carriage, has never been included in the ESR data, because what is not seen, can't become a statistic. The antibody tests, if used to prove the existence of "suspected whooping cough" in a contact with no significant symptoms, ... could result in an antibody test result becoming classified as a confirmed case, or ... a useful "statistic".
Both the newer PCR and antibody tests could substantially increase the ESR confirmed case numbers. That increase would NOT actually represent a greater spread of infection levels in the community, but would be a classic example of "when you look under every possible stone, you will find many more slugs". This is a more "up market" version of what happened in UK, Japan and Sweden after those three countries stopped using the whooping cough vaccine.
Who could benefit most from an artificially created increase
in pertussis case numbers?
People who want to "create data", to provide government officials or media with supposed "gold standard evidence" purportedly showing an increase in whooping cough cases.
These expensive tests with serious potential problems which render the science highly questionable, are now being implemented by public health zealots, ... committing and diverting millions of dollars of public health money... for highly dubious benefits.
Is the new diagnostic criteria driven by their need to increase their "control" over people, and advocate ....
yet more ...... whooping cough booster vaccines for everyone .....
Would the creation of any such control, and expectation of unquestioned compliance, be understood to fly in the face of the fact that New Zealand now has the highest ever vaccination rate for whooping cough, in history - with the most number of whooping cough vaccine boosters ever?