Skepticism about science and medicine

In search of disinterested science

HPV, Cochrane review, and the meaning of “cause”

Posted by Henry Bauer on 2018/10/27

HPV does not cause cervical cancer; HPV vaccination can be deadly mentions that Peter Gøtzsche had been expelled from the Cochrane Collaboration, causing some resignations from the Cochrane Board. For more about that, see what psychiatrist Peter Breggin has written about Gøtzsche: THE REFORM WORK OF PETER GØTZSCHE, MD
and what Gøtzsche himself has written: Disagreements in interpreting the Cochrane Spokesperson Policy

The Cochrane review of HPV vaccines, Prophylactic vaccination against human papillomaviruses to prevent cervical cancer and its precursors states, “Persistent infection with high-risk human papillomaviruses (hrHPV) types is causally linked with the development of cervical precancer and cancer. HPV types 16 and 18 cause approximately 70% of cervical cancers worldwide”.
But that has never been proved. The belief that HPV — or rather that a few of the 150 or 200 strains of HPV — cause cervical cancer is based solely on a statistical association, which — how often must this be said — never proves causation.
As I pointed out in HPV insanity,
“the risk of developing cervical cancer if infected with HPV is roughly 12,000 out of ~40 million . . . In what sense can it be said meaningfully that HPV causes cervical cancer, if that happens to one HPV-infected woman in every 3000?”
To a (one-time) chemist like me, the notion of attaching the label “cause” to something that happens once in 3000 attempts seems utterly absurd.

Another way of looking at this would be to say that 3000 women or girls need to be vaccinated to avoid one case of cervical cancer. In other words, the number needed to be treated, NNT, is 3000; whereas for any desirable medical intervention, NNT should be a small number. That generalization acknowledges that every medical treatment comes with a certain degree of risk that harm rather than benefit will ensue. In this particular case, “reports of adverse effects now total more than 85,000 worldwide. Nearly 500 deaths are suspected of being linked to quadrivalent Gardasil or Gardasil 9” (HPV does not cause cervical cancer; HPV vaccination can be deadly).
Since there exists no systematic, mandatory, global system for reporting adverse events resulting from medical treatment, the number of adverse events and of actual deaths are likely to be considerably higher. As the claimed benefit of the vaccination has never been demonstrated, the risk-to-benefit ratio would indicate that HP vaccination is not a good idea; see my earlier post about NNH and NNT for HPV vaccination, HPV vaccines: risks exceed benefits.
On the basic question of whether any strains of a HPV do actually cause cervical cancer, a serious supporter of the vaccines illustrates the supposedly causal process in this way:

That perhaps makes a bit clearer, why only about 1 in 3000 HPV-infected women ever experiences cervical cancer. Infection may clear; progression may be reversed by regression; and lesions do not necessarily lead to invasive cancer. There are, in other words, at least four distinct processes here, and there are presumably reasons why each of these happens or does not happen. In these circumstances, how could it be legitimate to identify HPV as the cause of the cancer?
In everyday talk, to say that A causes B is usually understood to mean that when A occurs, then B always follows — in other words, that A is a sufficient cause of B; and also, when B has occurred and we want to know why, and we hear that A can be a cause of B, we often jump to the conclusion that only A can cause B, in other words that A is a necessary cause of B.
However, in the matter of HPV and cervical cancer, HPV has not been demonstrated to be either a sufficient or a necessary cause of cancer.

Surely it is misleading to proclaim, as official agencies do and the meda parrot, “HPV causes cervical cancer”.


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