AskUs: Why are vaccinations controversial?

So one of our readers asked us this question the other day: Why are vaccinations controversial?

ANSWER

It all started with this rather deeply flawed study by a guy named Andrew Wakefield. Its conclusions rather profoundly overstep the actual scope of the study, and its results have never been replicated in many attempts. Most egregiously, he cherry-picked his sample from a much larger group — basically throwing away data points he didn’t like with total abandon. For a study that relies so heavily on statistical methodologies, that makes his conclusions worse than useless. It has since been retracted, which was a journal editor’s way of saying “screw you, this paper is a disgrace, can we all stop talking about it now?”

The study linked is the only study ever to suggest such a link between MMR vaccines and autism, and it has been fairly thoroughly debunked. Here’s a Washington Post column discussing it in a little more detail.

It should have ended, then, with the retraction. Wakefield, however, decided this one study was evidence enough to turn his whole career into a personal crusade against vaccines. Even more unfortunately, he somehow caught Jenny McCarthy’s attention, and she has turned it into a personal crusade. And once a little factoid enters the public mind, and especially when it is associated with any sort of celebrity, a retraction of an academic paper isn’t going to be enough to knock it out.

That’s how the autism – vaccination link started, which is what gets press nowadays. However, there intrinsically are small risks associated with vaccines — you are triggering an immune response which has a potential for serious side effects. Modern vaccines that are widely given out tend to be much safer than historical vaccines (e.g., that were more likely to use live viruses or use materials that could cause severe allergic reactions). Its overwhelmingly clear that the benefits of vaccination and herd immunity greatly outweigh the minute risks of vaccination, but its misleading to imply there are no risks.

This is why every vaccine ever developed isn’t given to every individual. For example, the small pox vaccine isn’t regularly given out in the US anymore (unless you would be responding to bioterrorism/health worker), as (a) smallpox was eradicated in the US (due to past vaccination programs), and (b) about 1 in every 1000 individuals has a severe reaction (not life-threatening) and about 1 in a million will die from the vaccine. (Though vaccines are stockpiled for every citizen in the event of a smallpox outbreak). –Source

If you look at say pertussis (whooping cough), thousands of Americans used to die each year and hundreds of thousands got significantly ill, before the vaccines largely eliminated it, though it is creeping back. In the 1980s there was a vaccination scare that pertussis may have been linked to permanent brain damage in very rare cases (e.g., ~50/year in the US). However, no actual causal link was ever found and its still clear the benefits of widespread vaccination outweighed the risk, as hundreds of thousands used to get seriously ill and thousands would die each year from whooping cough.

So there’s a tragedy of the commons dilemma going on. Skipping vaccination in a society with herd immunity doesn’t affect you at all, as you aren’t likely to ever encounter the disease as everyone you know is protected against it. It slightly helps as it eliminates the very small possibility of being the one in a ~million with serious side effects. However, living in a society without herd immunity, you have a very high chance of being the one in ~thousand who gets and dies of a vaccine-preventable disease. So vaccination is largely about societal responsibility.

One thing that sometimes gets missed in this discussion is that vaccines are under great scrutiny worldwide, and as new vaccines are introduced, data is always being collected on adverse events reported. That data obviously has to be carefully analyzed to try to sort out whether there might actually be a causal link, or whether it is merely a case of correlation; unfortunately, it is only natural to blame a new symptom on whatever may have changed in your routine of late. If you just got a vaccine recently before some major illness onsets, it’s the way the human mind works to “blame” the vaccine for the illness, but obviously the two may be entirely unrelated.

A great recent example of this is with the H1N1 vaccines. There were two variants of the vaccine: one with an adjuvant used mainly in certain European countries (so far as I know), and one without adjuvant (for those in the US, this is what we got). As it turned out, there was a small but significant trend in the countries that used the adjuvant vaccine indicating an increase in narcolepsy. It is still not known if this has anything to do with the vaccine; narcolepsy (and in particular, narcolepsy with cataplexy) is rare enough that minor changes in its incidence are rather small, particularly in countries with relatively small populations to begin with. Hopefully with further analysis of the data and by studying the affected cases over time, they can come up with a more definitive answer. Narcolepsy, unlike autism however, is already know to be an autoimmune disease which is provoked by abnormal immune response to certain stimuli; not all of the stimuli which can provoke this response have been identified.

As for autism, it’s certainly possible that these individuals, like narcoleptics, have a genetic predisposition which is activated by some process (in the case of narcolepsy, as I said, an autoimmune process). But it doesn’t make sense to change our vaccine policy to prevent autism; rather, we need to figure out how to detect who is susceptible in the first place.

So vaccines do have real risks, but their utility so vastly outweighs the cost that it’s not even worth considering whether there is a reason not to vaccinate a good portion of the population.