SciBlogs

Archive September 2009

Gardasil Post-licensure Study Darcy Cowan Sep 27

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Last month the Post-licensure safety study for Gardasil (the HPV vaccine) was released. The study focused on the reports of adverse events as reported to the VAERS database by the manufacturer, doctors and patients or caregivers. Much has been made by detractors of the vaccine about the serious alleged side effects that have struck young women given the course of injections. These allegations have been supported by referring to the VAERS database itself so if they are valid they should be upheld by this study.

Of the 12,424 reports that VAERS received in the 2.5 year period following implementation of the vaccine, 772 (6.2%) were classified as “serious”, the total number of vaccine doses distributed in this period was 23 million. The category of “serious” was defined according to the FDA regulatory definition of an adverse event that “is life threatening; results in death, permanent disability, congenital anomaly, hospitalization, or prolonged hospitalization; or necessitates medical or surgical intervention to preclude one of these outcomes”.

It must be noted at this point that the VAERS database cannot determine causality, the events reported merely have to occur after vaccination takes place. Therefore anything that happens to a patient in this time frame that someone thinks might be related to the vaccine may be entered. I point this out only to remind that while we may be looking at vaccine safety life does go on, accidents happen and co-incidences occur. The point of a study such as this is to determine if these events are occuring at a frequency higher than what we would expect in the normal population. In other words, is there really a correlation between these events and the vaccine or is is simply a statistical fluke.

The study looked into each type of adverse report in detail and attempted to answer the above question, does the rate of reporting exceed that which would be expected in the general population? In almost all cases the answer appears to be “No”, the exceptions to this were reports of syncope (fainting) and venous thromboembolic events (blood clots), this finding will certainly be followed up in future studies. Curiously one of he more prominent adverse effects that has been concerning many on both sides of the debate, Guillain-Barre´ Syndrome was not found to occur more than expected.

Guillain-Barre´ Syndrome is an auto-immune condition that can be brought on by vaccines but also by normal infections. The syndrome is caused when the immune system is stimulated by an antigen but then starts to target the body’s own nervous system, it usually exhibits as an ascending paralysis noted by weakness in the legs that spreads to the upper limbs and the face along with complete loss of deep tendon reflexes. As vaccines are made to induce an immune reaction the link between vaccines and the syndrome is biologically plausible and not controversial in the medical community.

The study concludes favourably but cautiously, as scientific studies are wont to do:

Vaccination with qHPV has the potential to decrease the global morbidity and
mortality of HPV-associated diseases, including cervical cancer. After hepatitis B vaccine, which can prevent liver cancer, qHPV is only the second vaccine licensed with an indication to prevent cancer. The postlicensure safety profile presented here is broadly consistent with safety data from prelicensure trials. Because VAERS data must be interpreted cautiously and cannot generally be used to infer causal associations between vaccines and AEFIs, postlicensure monitoring will continue, and identified signals may be
evaluated using epidemiologic observational studies.

The full study can be found here, a summary of the study here and a comprehensive discussion of the study here.

Posted in Medicine, Sciblogs, Science Tagged: gardasil, Health and Medicine, Medicine, study, Vaccination, Vaccines, VAERS

Harriet’s Toolbox Darcy Cowan Sep 26

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Harriet Hall of the Science Based Medicine Blog gave a talk at the Skeptic’s Toolbox workshop at the University of Oregon in August. The power point slides for this talk are now up on the Skeptics Toolbox website for all of us to benefit from. Head over there and check it out, the talk was titled “Tooth Fairy Science and Other Pitfalls: Applying Rigorous Science to Messy Medicine.” and is full of info and humour. Highly recommended.

Posted in Medicine, Sciblogs, Science, skepticism Tagged: Science and Society

Careful What You Fish For… Darcy Cowan Sep 23

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This story has already seen quite a bit of action in the Blogosphere but it was so good I couldn’t resist posting it here as well.

In recent years fMRI stories have become common and the technique has proved valuable for determining the internal state of a person’s brain while they complete specified tasks that allow researchers to draw conclusions about how our brains work. However the technology must be employed carefully otherwise spurious results will mar the integrity of the research. This point was amusingly demonstrated by Neuroscientist Craig Bennett when he decided to process the fMRI data collected from a dead Atlantic Salmon. Yep they scanned a fish.

Here’s a quote from the poster presented at the Human Brain Mapping conference.:

Subject. One mature Atlantic Salmon (Salmo salar) participated in the fMRI study.
The salmon was approximately 18 inches long, weighed 3.8 lbs, and was not alive at
the time of scanning.

Task. The task administered to the salmon involved completing an open-ended
mentalizing task. The salmon was shown a series of photographs depicting human
individuals in social situations with a specified emotional valence. The salmon was
asked to determine what emotion the individual in the photo must have been
experiencing.

After reviewing the data Bennett was surprised to discover a significant signal in the fish’s brain. Discussions on the metaphysics of post mortem mental lives of piscines aside, this was obviously a false positive. After much debate Bennett decided that this was a good example of why careful filtering of the data procuded by these machines is a must in order to draw valid conclusions. Read Bennett’s description of event’s at his Blog and see the poster based on the data Here.

Posted in Sciblogs, Science, Warped Science

Therapeutic Vaccines Darcy Cowan Sep 18

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Boost Your Immune System! It’s become the stock refrain from those selling supplements, remedies and assorted other concoctions. Most of the time this claim is pure marketing, all flash and no substance. The real immune boosters are far more effective and in many cases quietly do their job without the hype. We all are familiar with the practice of vaccination prior to contracting disease in order to prevent infections but can they be of use once a person is already sick? Turns out they can, these versions of our childhood and vacation friends are called Therapeutic Vaccines and they can be given to patients to combat illnesses that have already developed.

One of the more exciting uses these types of vaccine are being put to is to help our body deal with cancer. In particular difficult to treat breast cancers have been the focus of recent research by the Ludwig Institute for Cancer Research (LICR). The main problem in fighting cancer is that the cause of the disease is not a foreign invader but your own cells so specificity is difficult to achieve. This difficulty gives rise to the familiar side effects of chemotherapy (hair loss, nausea etc), so methods to target only cancer cells is the primary goal in most cancer research. In this case it is the products of a class of genes called CT-X genes, which stands for Cancer/Testis on chromosome X, that are being targeted by therapeutic vaccines. It turns out that this class of gene is not only expressed in male sex organs but also in many cancers, apparently almost exclusively in cancers.

These proteins are also expressed on the surface of the cancer cells which makes them a perfect target for vaccines. Preliminary research on cancer vaccines are already in the phase III stage, which means the large randomised trials that give the best evidence of efficacy and safety that come before a therapy is put to use in the wider community. It could be that vaccines will become an ever more important tool in our belt in the fight against a wide variety of illness. And it has the advantage of really stimulating your body to heal itself, an idea that is also widely used in alternative medicine circles. Double win!

Posted in Medicine, Sciblogs, Science

Astrologers Predict Planet!… Psych! Darcy Cowan Sep 11

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One of the hallmarks of science is the ability to make testable predictions, astronomy is no exception. While we may be reduced in most instances to passively receiving the electromagnetic emanations from beyond our horizons we can nevertheless form conclusions about the way the Universe works, formulate theories to explain those observations and make predictions to confirm (or falsify) those theories. This last step is a main distinction between science an pseudoscience.

The planet Uranus was discovered in 1781 by William Herschel, soon after it was found to be acting in a way contrary to what Newton’s laws predicted. The astronomers at the time attributed the perturbations of Uranus’ orbit to another unknown planet whose gravity was influencing the motions of it’s neighbor. Thus began the search for this mysterious next planet, this involved fiendishly complex calculations accounting for the effects of the other solar system bodies on Uranus and deducing the location of the unknown planet from the residual unexplained motions. Finally in 1846 using the results of these calculations Neptune was discovered.

Embarrassingly for astrologers neither of the new planets had been predicted by their own work, despite regularly making predictions on persons personality based on the alleged influences of just these sorts of heavenly bodies. While they quickly attributed influences to the new planets there were apparently no observed anomalies in their readings that even hinted at their existence prior to discovery by astronomers.

After having so successfully predicted Neptune astronomers moved onto the next unusually moving body in the solar system and attempted to apply the same reasoning. Mercury was also behaving badly as far as Newtonian physics was concerned so another new planet was introduced to explain it’s behavior: Vulcan. Another search was on.

Not to be left in the dust this time astrologers attributed influences to this new planet as well before confirming observations of it’s existence was made by astronomers. You don’t need to be an aficionado of current events to know that no such confirmation ever came, Einstein explained the discrepancies of Mercury’s movements with Relativity in 1915 after which the notion of Vulcan was relegated to the dustbin of science.

Though the was no longer any scientific need to invoke the existence of Vulcan astrologers seem to have held on to it anyway. Which leads to another central concept of science, falsification (alluded to above) the ability of science to discern between competing explanations, find the one that fits best and discard the blind alleys. Sometimes science doesn’t achieve this as well as we would like but pseudoscience seems not to do it at all, no idea is too ridiculous to keep.

The information above is much better laid out in the book “In Search of planet Vulcan” by William Sheehan and Richard Baum, a review of which may be found Here.

Posted in Psychological, Sciblogs