There are a lot of things I might have expected to hear discussed at last week’s Republican debate. I have to admit that vaccine safety wasn’t one of them. But then, I guess you never really know what Donald Trump is going to do.
At last week’s debate, Donald Trump repeated the tired old claim that vaccination is contributing to autism. “Autism has become an epidemic….I’m in favor of vaccines, but do them over a longer period of time, same amount but just in little sections, and I think you’re going to see a big impact on autism.” His rival Ben Carson (rightly) pointed out that at this point after years of research we have very strong evidence that vaccines do not cause autism. Just to mix things up and make life a little more interesting, however, Carson then conceded that perhaps we are giving too many vaccines and perhaps some of them are unnecessary, together with a cryptic remark about vaccines that don’t prevent “death and crippling”.
Rand Paul jumped in to (correctly) point out that vaccines are one of the greatest inventions in medical history and he’s all for them, but people should be free to decide when they want to be vaccinated. Finally (and although I don’t recall that she talked about it at the debate), Carly Fiorina has claimed that certain unspecified vaccines are not necessary for schoolchildren because the diseases they prevent are (she says) not communicable. It seems she’s probably talking about the HPV vaccine in particular, which is odd because HPV is communicable beyond a doubt; it spreads through sexual contact. Most cases of cervical cancer are caused by HPV, together with some anal and penile cancers.
It’s amazing there is so much hopeless confusion about vaccines. I guess there’s no point expecting The Donald to read the medical literature; he doesn’t need to see the evidence because he knows everything already. Or as he would say:
But it’s kind of disappointing Drs. Ben Carson and Rand Paul didn’t give Trump the kind of rebuttal his claims about vaccines really deserved. True, Carson and Rand are very clearly pro-vaccination, and unlike Trump they very clearly understand that vaccines do not cause autism. But what was this business about how maybe we’re giving too many in too short a period of time? I feel like Carson didn’t think through what he was going to say before he said it, and so he confused the issue instead of clarifying it.
The vaccines we are talking about have undergone extensive evaluation for safety. Let’s take the HPV vaccine, for example, since I suspect it’s one of the ones the candidates are talking about when they refer to “unnecessary” vaccines. I’ll refer to this review on PubMed which focuses on clinical trials with women patients; it discusses seven clinical trials for the vaccines now on the market; two for the GlaxoSmithKline bivalent version, five for Merck’s versions. (Other clinical trials that included male patients have also been conducted with very similar results.) All of the trials discussed in this review compared a group of patients receiving vaccine vs. a group of patients receiving placebo (i.e. saline water); two trials used either the hepatitis A vaccine or hepatitis B plus placebo as a control instead. Overall these seven trials enrolled ~44,000 women. There was no difference in side effect profile and adverse events between the patients receiving the vaccines and the patients in the control groups. In other words, so far as we can tell, the side effects of being injected with the HPV vaccine are about the same as the side effects of being injected with saline water. I think that’s about as safe as you can get.
Does the vaccine sometimes cause injection-site redness and swelling? Yes, but so too does an injection of sterile saline water. The human body is never very happy about somebody sticking a needle in there. Is the vaccine painful? Yeah, you bet, but so is an injection of sterile saline water. There have been studies looking for links between autoimmune conditions and injection of the HPV vaccine in teenage girls; no such links have ever been found.
You could of course argue the HPV vaccine is unnecessary, but this to me is an odd argument, because again, we know that virtually all cases of cervical cancer are caused by certain strains of HPV. Almost all of us who are sexually active have been or will get infected by HPV at some point in our lives (although not necessarily by one of the high-risk cancer strains). Usually there are no signs or symptoms or any way to know that you have been infected by one of these strains. The virus infects cells in mucous membranes and hijacks them, making changes to these cells that it needs in order to make copies of itself. The changes made by certain strains make the infected cells more likely to become cancerous years down the line. HPV is an example of what are called oncoviruses, viruses that change host cells in ways that make cancer more likely to develop; the Epstein-Barr virus is another example.
To cut a long story short: We know that most cervical cancers are caused by HPV. Immunizing for HPV is about as close as we can come at present to getting rid of a particular kind of cancer. Why wouldn’t we want to do that? Why would you characterize that as “unnecessary”?
And on that note, let me go back to these remarks about “unnecessary” vaccines. Which vaccines do the candidates believe are “unnecessary”? The vaccine for rubella, a disease that causes birth defects? The vaccine for diphtheria, which kills 5-10% of infected patients (20% of infected babies)? The vaccine for measles, which is one of the most contagious airborne diseases we know? The vaccine for Hib, which used to infect 20,000 kids a year in the US and kill 3-6% of them? Once again, I suspect a lot of people have forgotten exactly how dangerous these diseases really are.
And let’s remember, the goal in many cases is to get rid of the disease, the way we did with smallpox, and then we can stop vaccinating for it once the disease is extinct. Nobody gets the smallpox shot anymore because smallpox has been wiped off the face of the Earth. We’re pretty darn close with polio, but there’s still some pockets left in Africa and Pakistan and the Middle East, partly because the Taliban decided to spread rumors the polio vaccine was actually a CIA conspiracy. End result: Some Pakistani families believed the rumors and won’t take it. The years of warfare and chaos probably haven’t helped either. It’s a frustrating situation, because we’re so close to making the polio virus extinct, and if we could do that it would be one less vaccine everybody would have to take. Wiping measles off the face of the Earth would be a lot tougher but it’s possible. Tetanus, of course, is a soil bacterium so we can never get rid of it completely. But in many of these other cases, it is possible to completely wipe out the bug, if you could get everyone everywhere vaccinated, and then the vaccine would become unnecessary.
Enough of this. Back to Rand Paul’s argument, which is very different. Rand Paul is not arguing any of these vaccines are unnecessary or unsafe; if I understand him correctly, he’s making a different argument. His take seems to be that sure, vaccines are safe and sure, they’re great, but freedom is the most important thing there is, so people should be free to vaccinate or not and do it whenever they like. If you want to get people to vaccinate, you should explain the benefits rather than mandating vaccination. I have a lot of sympathy for this argument to the point where it’s almost tempting to agree. It sounds nice in theory: mandates are unnecessary and undesirable; just explain how great vaccination is and everybody will do it of their own free will. Unfortunately, some people don’t seem to be interested in evidence from clinical trials; like Trump, they’ve decided vaccines must be dangerous for one reason or another. When they refuse to vaccinate their children, their children can then pick up the disease and transmit it to others (no vaccine is 100% effective). If the % of the population that is vaccinated falls too low, we end up with an outbreak or an epidemic.
The CDC’s goal is to maintain a sufficiently high percentage to have so-called “herd immunity”, i.e. the % of the population that’s immunized is high enough the disease cannot spread, so it dies out. One way to make sure that happens (possibly and unfortunately the only way) is to mandate vaccination for highly contagious diseases like measles; if you want your kid to attend school, they need to get vaccinated.
So is that curtailing people’s freedom? I don’t know. I think when it comes to infectious disease, you also have to consider public safety. It’s kind of like texting while driving or driving drunk. Does “freedom” mean you have the freedom to get behind the wheel drunk? Does “freedom” mean you have the freedom to text while you drive? I think most of us would say these are cases where your behavior is likely to kill someone therefore in those cases public safety takes precedence over your personal freedom which at all other times is more important. This is kind of an opinion question rather than a scientific one but I think vaccination is a similar case.
One last thought about this whole mess. Perhaps it’s just me, but it seems a little odd to me that the Republicans are arguing about vaccination. Trump’s kind of anti-vaccine rhetoric used to be more common among certain specific Left-leaning groups. I’m not entirely sure how it has migrated to the Right. Either way, it’s kind of annoying that in addition to politicians debating whether climate change is real, they are now debating whether vaccines are safe. What next? A debate on whether Heisenberg’s uncertainty principle is really valid? Maybe some politician or another will take up arms against the theory of gravity or the Second Law of Thermodynamics. After all, Trump has already claimed the Chinese invented the concept of climate change in order to “make US manufacturing non-competitive”. If climate change is really a foreign conspiracy, why not the rest of science too?