Thursday, October 1, 2009

Are vaccines safe?

The H1N1 pandemic is bringing into focus not only the world's vulnerabilities vis a vis the spread of an infectious disease, but also our complete lack of a framework in which to make rational choices about prevention. The cornerstone of preventive efforts for any significant infectious disease is vaccination of a large swath of the population. The rapid development and approval of the H1N1 vaccines is both a blessing and a curse, given the sophomoric level of discussion about its risks and benefits. By coincidence this discussion has extended into the world of HPV vaccination, with a high profile death of a 14-year-old girl in the UK one hour following inoculation with Cervarix, the GSK's HPV shot. Though upon a post-mortem examination it is clear that the girl's death was a result of a malignant tumor invading her chest and not of Cervarix, the level of panic and skepticism about the vaccine is illustrative of the polarization of public opinion on the very philosophy of vaccination itself.

Why do we even have vaccines? To put it simply, vaccines are there to prevent highly infectious agents from causing mass morbidity and mortality. In the US, states mandate that children undergo certain vaccinations as a prerequisite for attending school. In fact, save for a handful of states where parents can express intellectual objections to some vaccines, in most states, including my own, the only acceptable reason for not vaccinating a child is a religious objection. And this is an all-or-nothing situation, where you are forced to either get the entire panel of shots or nothing. These laws, written decades ago, have taken individual decision making out of the public's hands. They leave no room for engaging in an educated risk-benefit analysis for the individual situation.

Rabid vaccine advocates would argue that there is never a need to make individual decisions in diseases where a vaccine is available. Well, let's take the chicken pox vaccine. Here is a childhood disease that is indeed highly contagious, but only causes a self-limited nuisance illness with a very low risk of complications in the pediatric age group without underlying conditions. In the US the disease was associated with ~10,000 hospitalizations and on average 105 deaths annually in the pre-vaccine era. So, is this really a big deal? Well, yes, from the perspective of those families suffering the 105 fatalities. But what about the societal concern? This is well summarized in the recommendation rationale from the American Academy of Family Physicians
Because chickenpox is so contagious, a child with chickenpox shouldn't go to school or day care until all the sores have dried or crusted. Many parents miss work during the time their child has chickenpox. Because of the lost time from work, chickenpox can be a significant cost to parents of children who get the illness. [emphasis mine]
So, there is clearly an economic risk that drives at least some of the rationale for requiring this vaccine. This then begs the question: should economic considerations ever drive a government mandate for vaccination? Note, economic considerations do not fall into what I put forth as the rationale to vaccinate: to prevent spread of highly contagious disease that causes wide-spread morbidity and mortality. Now it becomes about the money. So, does it not stand to reason that I as a parent should be able to take into account my personal situation with respect my aversion to missing work days to stay home with a sick child and make this vaccination decision myself?

Unfortunately, I do not believe that most citizens are equipped with the skills to make these informed choices. Since we have broadly accepted the government's judgment as to who should get vaccinated with what, we have not been taught systematically to make these choices rationally. And here we are, in 2009, faced with the swine flu and HPV choices: to vaccinate or not?

Ignorance is fertile ground for breeding fear. Hysterical rhetoric on both sides, anti-vaxers and vaccine apologists, is promoting a climate of confusion. When a radio program polls its listeners on whether or not they believe the H1N1 vaccine is safe, what are they looking to accomplish? As scientists we know that the concept of safety does not exist in a vacuum. How do you define safe? Safe for whom? Is there a gradient of safety? And what do the loud and often non-sensical caller responses accomplish but to create more noise at the margins?

A more constructive approach in the short-term would be to present the populace with facts -- both risks and benefits of both the diseases and the vaccines against them. (And yes, the reality is that diseases AND vaccines will have risk-benefit profiles that differ for different people.) But this short-term tactic will not solve our general inability to make rational choices when faced with complex ideas. This shortcoming needs to be addressed in our educational institutions. This knowledge will serve us in far more ways than just deciding whether or not to vaccinate our kids against chicken pox.      


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