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We may not know everything, but we know what we know from prior knowledge

For one of my classes this term, I was reading the story of John Snow and how he put together a bunch of clues in order to convince London authorities that their cholera epidemic came from a water pump, was transmissible from person to person, and that it could be caused by some sort of microorganism. I think that his reasoning and actions were nothing short of genius. See, at that time, everyone with a good reputation and good education in science and medicine thought that diseases were transmitted by “miasmas” or “bad air.” In the case of cholera, the predominant thinking was that “effluvia” emanated from the sick people (or their bodies once they died) and that healthy people would get sick by breathing in that effluvia.

It would be quite a number of years before the idea of microorganisms causing disease — what we call “germ theory” — became the proven and accepted way in which diseases were transmitted. This was the case even with the many clues that infectious diseases didn’t emanate from a vacuum. Though John Snow was not the first one to have these ideas and put them forth as possibilities, he was the first one to gather all the available evidence and present it in a coherent manner.

Even with his prestige as a physician, and his “fame” for having helped to stop a deadly cholera epidemic in London, John Snow was attacked quite vigorously by scientists who wanted to hold on to the notion of miasmas. They even went as far as implying that Snow’s work was impeding the progress of science towards helping other people. If this all seems familiar to you, it should.

We live in a very, very, very connected society. A scientific discovery made today will likely be well-known in a matter of weeks if not days. As with John Snow, if the discovery or the theory arising from some new way of doing things is revolutionary enough, the response to it will be vigorous. That response will also come from all sorts of different directions, including from other scientists.

The difference between now and the times of John Snow is that science works just a little bit differently.

Consider the recent paper by Dr. Brian S. Hooker, the paper I criticized a few days ago. In his paper, Dr. Hooker makes the claim the MMR vaccine caused autism in African American boys. Like John Snow, Dr. Hooker’s assertion is controversial at the least. After all, the overwhelming majority of reasonable scientists all agree that the MMR is not associated with childhood autism. So are we, the scientists, being like the miasma apologists of John Snow’s time? No, not at all.

As I pointed out, Dr. Hooker made several missteps in his statistical analysis, and his epidemiological reasoning was not sound at all. Had he done the statistics correctly by using the proper statistical method and adjusting for confounders — and had he treated the data as that of a case-control study (as it was initially collected) and not that of a cohort study — then his assessment of the evidence would have been held as valid and, at the very least, would have made us all go looking for more evidence. Instead, and unlike John Snow, we get from Dr. Hooker and Andrew Wakefield nothing but leaked and incomplete audio recordings and screenshots of text conversations. We don’t get any more evidence or any answers to the legitimate questions that reasonable scientists have raised of the Hooker study.

In essence, John Snow did not rely on theatrics to get his points across. He used the tools of science to preemptively answer all the questions that would arise form his epidemiological analysis of the outbreak of cholera. He stated his case with evidence, and he made sure that his reasoning was sound and that his thesis was grounded in reality.

We can see a similar “questioning” of the established science in those who state that HIV does not cause AIDS. For example, Peter Duesberg, PhD, has asserted in numerous scientific writings that HIV is a “passenger virus” and that the virus does not cause AIDS. He has put forth a theory that it is actually drug abuse, malnutrition and even antiretroviral therapies that cause AIDS, so finding HIV in an AIDS patient is purely coincidental. Is he the John Snow of our time? Again, the answer is no.

We have determined by observation and experimentation that people with HIV who go untreated will develop AIDS. Likewise, people who develop AIDS all have HIV. Also, people without HIV do not develop AIDS. There is no evidence of people without HIV developing AIDS, which throws a wrench into Dr. Duesberg’s theory. He’s been at it for a while, and still no HIV-negative people with AIDS, which tells us that he is more like Snow’s detractors than like Snow himself. Dr. Duesberg wants to hold on to an outdated idea that is not based on the best evidence. (In the same way that bigots still to this day call AIDS a “gay disease.”)

I could go on and on about how the so-called “scientific mavericks” are not at all like John Snow, a “maverick” in his own right. His ideas, in my opinion, were not all that “crazy.” It’s not like he went completely and absolutely against the established scientific ideas of his time. Instead, he built upon the established scientific ideas and, through his analysis of the evidence, determined that the miasma idea needed tweaking. His work would eventually be proven to be true, especially after Pasteur and Koch and all those other scientists determined that infectious agents really did exist and did not originate out of nowhere. Unfortunately for science deniers, their work will not be proven to be true, and this they will not be remembered hundreds of years from now for their work… Maybe only for their stubbornness. Maybe.

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René F. Najera, DrPH

I'm a Doctor of Public Health, having studied at the Johns Hopkins University Bloomberg School of Public Health.
All opinions are my own and in no way represent anyone else or any of the organizations for which I work.
About History of Vaccines: I am the editor of the History of Vaccines site, a project of the College of Physicians of Philadelphia. Please read the About page on the site for more information.
About Epidemiological: I am the sole contributor to Epidemiological, my personal blog to discuss all sorts of issues. It also has an About page you should check out.

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