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    HPV Vaccine Risk
    By Josh Witten | October 13th 2009 01:37 PM | 10 comments | Print | E-mail | Track Comments
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    The safety of the HPV vaccine (marketed as Gardasil in the US) has recently been a hot-button issue. The politics of government vaccine mandates has become conflated with the medical research. Politically, it is perfectly reasonable to oppose government mandates on principle. Economically, it is perfectly reasonable to be skeptical of the HPV vaccine manufacturers wanting to market their product. Medically, however, it is not reasonable to support one's political or economic positions with the claim that the vaccine is unsafe.

    David McCandless of Information is Beautiful summarizes the available research on HPV vaccine safety in yet another compelling graphic. In summary, Gardasil is no more dangerous than living.
    by David McCandless

    Comments

    Gerhard Adam
    While I don't necessarily disagree with your sentiment, your statistics are suspect.

    By showing a 500:1 chance of dying from cervical cancer, it hasn't been established whether that is a statistic against all deaths for women, or only for those that contracted cervical cancer.  Since the statistic for getting cervical cancer is not mentioned, the benefit of HPV can't actually be articulated.
    It would also be useful to know how many that get HPV may still get cervical cancer.
    Gerhard Adam | 10/13/09 | 14:00 PM
    jtwitten
    It is not my graphic, as I made abundantly clear. Click the image or the links. McCandless includes a discussion of the difficulty of compiling the statistics.
    Josh Witten | 10/13/09 | 15:17 PM
    jtwitten
    12000 women get cervical cancer each year and 4000 die of cervical cancer.
    Josh Witten | 10/13/09 | 15:31 PM
    Gerhard Adam
    The calculations aren't right.

    Instead, the odds are calculated using the National Safety Council’s method. That is:

    population of United States / number of deaths per year

    That gives the one year risk rate. Then if you divide that number again by the average US lifespan (77.8 years) you get the lifetime risk. See the risk chart here.
    To use the full human lifespan reflects the odds more favorably, despite the fact that for a good portion of it (20% +), the subject would never have taken Gardasil. 

    Presumably they didn't include males in the previous determination (i.e. population of the U.S.).

    Gerhard Adam | 10/13/09 | 15:33 PM
    Gerhard Adam
    Josh, I'm not holding you to these statistics, but I'm questioning the basis by which some of these numbers were derived in the original article.

    The population of women in the U.S. (2008) is about 304,059,724 * 50.7% = 154,158,280

    The article indicates that 20,000,000 doses have been given (of which it was estimated that about 2 per person occurred).  So that means only 10,000,000 women have gotten a dose or about 6.5% of the female population.

    While the indications are that Gardasil is safe, I would also suggest that statistics like this are largely incomplete and certainly not predictive of long-term behaviors.  Given the small number of women that have been vaccinated and the short-term over which this has occurred, it is presumptious to extrapolate a prediction out over 70-80 years with any degree of confidence.

    We can't even conclusively state how effective Gardasil is in preventing cervical cancers since no studies have run long enough to monitor a female throughout her life (even though we do know that with the vaccine, some types of HPV caused cervical cancers are still possible).

    Bear in mind that the source for these numbers also indicates that you have a 1 in 70,000 chance of being legally executed.  While such a number may be useful to determine the distribution of probabilities for a population at large, it is completely bogus in terms of assessing personal risk.

    My point is that no one can state conclusively how this will all work out, or if it's even the best strategy.  The best that can be said, is that it appears that Gardasil is safe and that it appears to be the best chance of protecting against HPV caused cancers.  While this isn't a guarantee of blanket protection it can improve the odds in avoiding a known cause of cervical cancer.

    Gerhard Adam | 10/13/09 | 16:46 PM
    jtwitten
    Which is essentially an extremely long argument agreeing that the argument against Gardasil that it is unsafe is not a legitimate argument.
    Josh Witten | 10/13/09 | 20:21 PM
    Gerhard Adam
    In summary, Gardasil is no more dangerous than living.
    My point is that the preceding statement is based on statistics that aren't directly applicable to assessing personal risk.  Gardasil hasn't been tested or available long enough to make this statement.  This is what opens the door to skeptics that want to emphasize the risk, because both sides tend to be sloppy in their statistics.

    In truth, no one actually knows how this is going to play out, since the vaccine is technically only effective for four years.  It's not certain whether a booster will be needed or another round of vaccinations. 
    "...Gardasil and Cervarix prevent nearly 100 percent of the precancerous cervical cell changes caused by the types of HPV targeted by the vaccine for up to 4 years after vaccination among women who were not infected at the time of vaccination"
    In addition, the number of women given dosages is actually much lower than I calculated since that was based on two dosages, when it should be three.

    Since the point of vaccinating girls before they become sexually active is one of the prime motivators to get this going, it does raise the question about how reasonable this will all be if it may only be effective for four (4) years.  Another point is to prevent these cancers in women aged 30-40 which suggests that there is a rather large gap in the protection being offered, and the large unknown about whether such a short effective period is actually useful.

    Gerhard Adam | 10/13/09 | 20:53 PM
    jtwitten
    Actually, that line is based on this quote from the CDC:
    There are no unusual patterns or clustering in the deaths that would suggest they were cause by the vaccine.
    Essentially, in any study that follows millions of people, some people will die. We'd find the exact same thing if we followed the same number of people taking sugar pills.
    Josh Witten | 10/13/09 | 21:17 PM
    jtwitten
    Gerhard, the time period of effectiveness can be accommodated in the cost-benefit analysis. Long-term analysis always conveys the risk of becoming paralyzing. A frequently cited concern is that long-term risks will be missed in favor of short-term benefits. Fortunately and likely for biologically reasonable reasons, the time periods for benefits and costs are usually of similar scales, when we are not considering long-term exposure effects. I believe these stats were representing the odds that X would be the cause of death. The fact that the risks differ by, roughly 3 orders of magnitude (and that is attributing all deaths among subjects to the vaccine, which is a statistically unreasonable assumption) means that the central message of these statistics will probably be robust to nit-picking.
    Josh Witten | 10/15/09 | 15:50 PM
    Gerhard Adam
    No problem, then that's all that needs to be said.  As you well know, there are many people that will be paranoid or unnecessarily fearful regardless of the assurances or the research data.

    My only point, is why make it easy to raise such disputes by making statements or using statistics that can be challenged.  If would be much easier if it was simply stated that we consider the benefits to be "X" based on this study which indicates that there are no immediate risks from the vaccine.  However, long term studies have not been conducted, but our current experience suggests that risks will not, or do not increase over time or within increased vaccinations.

    If people want to opt out because they think it is too risky, then so be it.  It is wrong to present the data to suggest certainties when none exist, just as it is wrong to raise the alarm when none exist.

    Gerhard Adam | 10/15/09 | 16:13 PM