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Herd Immunity

Some infections can be eradicated from the face of the planet. Smallpox is the one example of disease eradication to date. Smallpox still exists in US and Russian labs, but there has been no wild cases since 1977.  It is, like the Dorothy, history.

Why were we able to eradicate smallpox?  Three reasons:

1) There is only one form of smallpox. Unlike influenza that changes from year to year.  So only one vaccine needed.
2) By what appears to be a once in a universe miracle, every county cooperated with  the WHO (much like we all cooperate with the IRS) so the entire planet received the vaccine. Once enough people were vaccinated, the disease was unable to perpetuate itself and spread and so died out.
3) Unlike bacteria, there are no asymptomatic smallpox carrier states.  Eradicable viruses usually cause symptomatic disease and do not result in asymptomatic, infectious carrier states that serve as a reservoir for infecting others.  HIV and Herpes cause chronic asymptomatic infections and will probably never be eradicated.

There are other diseases that are theoretically eradicable, like measles and polio. They have one antigenic type, have no carrier state and, if the entire world could be vaccinated, the disease would cease to exist in the wild.  I am sure there would be biologic weapons labs that would always carry a vial or 2 of every infection. Just to be safe.
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Posted in: Public Health, Science and Medicine, Vaccines

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Will The Real, Silent Majority Please Stand Up – To Oprah and Jenny McCarthy?

Much to my surprise and delight, my recent blog post about Jenny McCarthy’s  “educational” video was picked up by several other blogs and websites, resulting in a small flood of emails applauding my efforts to expose dangerous pseudoscience. I had braced myself for what I assumed would be an onslaught of hate mail (what else would irrational folks do about a sensible warning message?) and found that instead I received a small number of high-fives from advocates and health organizations committed to cutting through the rhetoric and providing accurate information about vaccines. Perhaps the hate is still in the mail?

I began wondering who is in the majority on the issue of vaccines – those who want to study concerns carefully and accept what the science shows, or those who are fixated on blaming vaccines for diseases they don’t cause, despite all evidence to the contrary.

Since the latter are louder than the former, one does tend to feel as if the world has gone a bit nutty. And when celebrities like Oprah Winfrey promote the unfounded anti-vaccine rhetoric of Jenny McCarthy, sensible parents across the country begin to shudder. But when will this shuddering lead to action?
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Posted in: Science and the Media, Vaccines

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Should Vaccines Be Compulsory?

In the US children must have proof of vaccination before entering the public school system, although it is becoming easier in many states for parents to gain exemptions from this requirement. In the UK there is no such requirement. This distinction has allowed for a comparison of the impact of scaremongering about the safety of vaccines and the effectiveness of campaigns to improve vaccination rates.

In the UK the scare that the MMR vaccine may be connected to autism (it isn’t) triggered by the bogus study by Andrew Wakefield resulted in a precipitous drop in vaccination rates down to about 78% overall. This is far below what is necessary for herd immunity, when immunity is prevalent enough to prevent a disease from spreading around a population. And the 78% figure is an average – but there are pockets where the number is even lower. This resulted in a surge of measles – from a low of less than 100 cases per year to 1,348 cases in 2008. The surge contniues despite an aggressive campaign to inform the public about the safety of the MMR vaccine.

By contrast the US has seen continued high overall vaccination rates of about 90%. The MMR and other vaccine scare came to the US a bit later than the UK but it is in full swing here, without much effect on overall vaccination rates.  However, we are beginning to see the emergence of low vaccination rates in specific communities, with subsequent outbreaks of measles (131 cases in 2008), mumps, and whooping cough.

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Posted in: Science and Medicine, Vaccines

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Adverse Effects of Chiropractic

There is a very good chance that you will feel worse after seeing a chiropractor.

According to a new systematic review, serious complications of spinal manipulation are rare, but 33-60% of patients experience milder short-term adverse effects such as increased pain, radiation of pain, headaches, vertigo and even loss of consciousness. The study, published in the journal Spine, involved searching PubMed and the Cochrane Library for the years 1966 to 2007. They identified additional studies by hand searching. They looked for all articles that reported adverse effects associated with chiropractic irrespective of type of design. They omitted any reports where patients had underlying diseases (osteogenesis imperfecta, expansive vertebral hemangioma, osteoporotic fracture, etc.) that predisposed them to complications with manipulation.

They found 46 pertinent studies:

  • One randomized controlled trial
  •  Two case-control studies
  •  Six prospective studies
  •  Twelve surveys
  •  Three retrospective studies
  •  115 case reports

They recognized that “the heterogeneity of the study designs did not allow conducting a formal meta-analysis.” But they did the best they could to make sense out of what they found. (more…)

Posted in: Chiropractic

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The Oprah-fication of medicine

OprahUnfortunately, a frequent topic on SBM has been the anti-vaccine movement, personified these days by celebrity spokesmodel for Generation Rescue Jenny McCarthy and her dimmer than dim boyfriend comedian and actor Jim Carrey. Unfortunately, it is a topic that is unlikely to go away. We’ve all speculated why the anti-scientific emotion-based notion that vaccines somehow must cause autism persists in spite of mountains of evidence to the contrary, but I think the question goes much deeper than that because it’s not just about vaccines. The anti-vaccine movement is but one of the most visible components of a much deeper problem in our public discourse, a problem that values feelings and personal experience over evidence, compelling stories and anecdotes over science.

I’m referring to the Oprah-fication of medicine in America.
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Posted in: Public Health, Science and Medicine, Science and the Media, Vaccines

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“Acupuncture Anesthesia”: A Proclamation from Chairman Mao (Part II)

An Anesthesiologist’s Perspective

The late John Bonica (1917-1994), one of the great anesthesiologists of the 20th century, has been called “The Founding Father of the Pain Field.” He developed this interest while treating wounded soldiers at Fort Lewis, Washington, during WW II. Shortly thereafter he became a pioneer of epidural analgesia and other forms of safe pain relief for labor and delivery. In 1947 he created the first multidisciplinary pain clinic, at Tacoma General Hospital, and in 1960 brought it to the University of Washington School of Medicine when he became the founder and first chairman of its Department of Anesthesiology. In 1953 he published the first comprehensive textbook on the subject of pain, the 1500 page Management of Pain. In 1973 he founded what is now the largest professional organization devoted to pain relief, the International Association for the Study of Pain (IASP).

Dr. Bonica was born in Italy. He came to New York City with his family when he was 11. His father died four years later and he became the major breadwinner for the family. He competed in wrestling while in high school and won both the New York City and state championships. Later he worked his way through college and medical school by wrestling professionally under the pseudonym ‘Johnny (Bull) Walker’, and according to several sources he was the “Light Heavyweight Wrestling Champion of the World.” He continued to wrestle while in the army but concealed his military identity by becoming, in the ring, the “Masked Marvel.”

At the time of the burgeoning Western interest in acupuncture in the early 1970s, Dr. Bonica became the Chairman of the Ad Hoc Committee on Acupuncture of the National Institutes of Health (NIH). In 1973 he was “selected by the Committee on Scholarly Communication with the People’s Republic of China of the National Academy of Sciences to be a member of the first official American medical delegation to visit the People’s Republic of China, and was given the responsibility of evaluating acupuncture and anesthesia as practiced in that country.”

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Posted in: Acupuncture, Medical Academia, Politics and Regulation, Science and the Media

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Homeocracy IV

In the three prior posts of this series I tried to analyze some of the defects in the randomized clinical rials (RCTs) of homeopathic remedies for childhood diarrhea. The first entry showed that the first two RCTs’ (done in Nicaragua) methods could not produce a meaningful result because of the way the RCTs were set up (methods.) The second entry showed that the results obtained in the first two trials were meaningless clinically even if assumed to have resulted from more legitimate methods. The same applied to the third trial in Nepal, analyzed in the third entry.

This entry  will suggest that the authors’ fourth paper (Jacobs J, Jonas WB, Jimenez-Perez M, Crothers D. Homeopathy for childhood diarrhea: combined results and metaanalysis from three randomized, controlled clinical trials.  Pediat Inf Dis J, 2005;22:229-234.)- a meta-analysis (MA) of the data from the three RCTs resulted in conclusions equally as meaningless as those of the three trials.

The MA authors – several of the same workers from the three RCTs – begin by agreeing that the data from the RCTs, taken individually, were of borderline significance:

In our previous three studies, we evaluated the use of individualized homeopathic treatment of childhood diarrhea … The results of the two larger studies (n = 81, n = 116) were just at or near level of statistical significance. Because all three studies followed the same basic study design , […] we analyzed the combined data from these three studies to obtain greater statistical power.  In addition we conducted a meta-analysis of effect-size difference […] to look for consistency of effects.

MAs and systematic reviews (SRs) are the two consensus methods for summarizing data from multiple individual studies. The inclusion and search methods of RCTs for SRs and MAs are similar, but the objectives of the two are a bit different, as are the forms of the reports.  In SRs, the results are summarized  in more in narrative form, whereas in MAs the data are treated mathematically and the results are defined in statistical terms.  Thus authors of SRs are freer to speculate on the degree of confidence that a method is effective based on what is shown by the numbers of positive and negative RCTs collected.  Authors of MAs usually limit their comments to what the mathematical formulation of the summarized data show.
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Posted in: Clinical Trials, Energy Medicine, Homeopathy, Science and Medicine

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Science And The Game Of 20 Questions

An audience member at a recent NYC Skeptics meeting asked me how I handled conflict surrounding strongly held beliefs that are not supported by conclusive evidence. As a dentist, he argued, he often witnessed professionals touting procedure A over procedure B as the “best way” to do X, when in reality there are no controlled clinical trials comparing A and B. “How am I to know what’s right in these circumstances?” He asked.

And this is more-or-less what I said:

The truth is, you probably can’t know which procedure is better. At least, not at this point in history. The beauty of science is that it’s evolving. We are constantly learning more about our bodies and our environment, so that we are getting an ever-clearer degree of resolution on what we see and experience.

It’s like having a blurry camera lens at a farm.  At first we can only perceive that there are living things moving around on the other side of the lens – but as we begin to focus the camera, we begin to make out that the animals are in the horse or cattle family. With further focus we might be able to differentiate a horse from a cow… and eventually we’ll be able to tell if the horse has a saddle on it, and maybe one day we’ll be able to see what brand of saddle it is. Each scientific conundrum that we approach is often quite blurry at the onset. People get very invested in their theories of the presence or absence of cows, and whether or not the moving objects could in fact be horses. Others say that those looking through the camera contradict one another too much to be trusted – that they must be offering false ideas or willfully misleading people about the picture they’re describing.

In fact, we just have different degrees of clarity on issues at any given point in time. This is not cause for alarm, nor is it a reason to abandon our cameras. No, it just gives us more reason to continue to review, analyze, and revise our understanding of the picture at hand. We should try not to make more out of photo than we can at a given resolution – and understand that contradicting opinions are more likely to be evidence of insufficient information than a fundamental flaw of the scientific method.
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Posted in: Science and Medicine

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Does the Flu Vaccine Increase Hospitalizations?

The Centers for Disease Control (CDC) currently recommends that children 6 month to 18 years old receive an annual flu vaccine. There are two types of flu vaccines used in the US: a live attenuated virus (LAIV) and a trivalent inactivated virus (TIV) vaccine. Both are safe and effective  – while efficacy varies from year to year, they are 70-90% effective in healthy adults. Efficacy is young children appears to be slightly less, about 66%.

There remains, however, many sub-questions about the flu vaccines and by the time researchers have thoroughly explored them vaccine technology is likely to have progressed, and therefore any new vaccines will have to be tested all over again.

One of those sub-questions about vaccine safety and efficacy is the net effect of the flu vaccine in children with asthma.  Some have raised concerns that the vaccine may exacerbate asthma, a 1-2% increased wheezing and 3% increased hospitalizations have been reported, although so far the bulk of the data suggests that both types of flu vaccines are safe in children with asthma.  There is evidence to suggest that the LAIV may be superior to the TIV in children, particularly with asthma.

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Posted in: Vaccines

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Another Kind of Evolutionary Medicine

Last month I wrote about a book on evolutionary medicine that I could not recommend. Now I’ve found one I can recommend. Marlene Zuk, an evolutionary biologist at the University of California, Riverside, has written a delightful book entitled Riddled with Life: Friendly Worms, Ladybug Sex, and the Parasites That Make Us Who We Are. She describes how our parasites and diseases co-evolved with us: as we developed better defenses, they developed better weapons. “We do not choose to have them, but our lives are unimaginable without them, and for better or worse, they have made us who we are.” Parasites have altered our bodies in ways that science fiction filmmakers could never have imagined. She even suggests that we can thank parasites for the fact that we reproduce sexually rather than asexually.

She advocates an evolutionary medicine that “places diseases and defects in an evolutionary framework to make sense of the apparent mismatch between the way our bodies often work and the way we would like them to.” Evolution did not design our bodies for health, but to maximize reproduction.

“Just because our species evolved in a different environment does not mean …that following the ways of the past is automatically going to free us from the illnesses of modern life.” She incisively debunks the myth of the Paleolithic diet and points out that if we wanted to copy our hunter-gatherer ancestors we would have no way of deciding which ones to copy – the ones from 10,000 years ago or the ones from 100,000 years ago; the Inuits or the Kalahari Bushmen. She also points out that evolution explains why humans vary and why one diet won’t suit everyone. (more…)

Posted in: Book & movie reviews, Evolution

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