Do we need more studies on vaccines, GMOs, climate change, etc.?

anti-vaccers want more studies but refuse to accept studies memeI frequently encounter people who state that, “I’m not anti-vaccine/GMO, I just think that we need more studies” or “we need more research before we take major action on climate change.” I have, however, noticed that whenever someone declares, “I’m not X” they usually end the statement with some pathetic justification for why they are in fact X, and that is definitely the case in this situation. The cry for more studies on vaccines, GMOs, etc. is nearly always hypocritical and stems from a willful ignorance about just how many studies there actually are. The reality is that topics like vaccines have been so well studied that they have achieved the status of settled science (please actually read the linked post before berating me over that term). So, the problem isn’t that there aren’t enough studies; rather, the problem is that people refuse to read or accept the hundreds of studies that we already have. To be fair, I have occasionally encountered people who asked for more studies out of honest ignorance rather than willful ignorance, and those people quickly retracted their statements once I directed them to the veritable mountain of published literature. That type of ignorance is fine. There is nothing wrong with not knowing something, then updating your view when presented with evidence, but in my experience, those people represent a tiny minority, and most of the people who demand more studies are doing so out of willful ignorance.

Note: Before I present some examples of this flawed excuse for denialism, I want to make it absolutely clear that I am not suggesting that we should be doing less research or should spend less funding on science. I am a scientist, and like most scientists, I spend a minimum of 60 hours a week collecting and analyzing data, writing papers, etc. So obviously I place a high value on scientific research, and I think that we need more of it. The amount that most governments invest in research is pathetic (granted, I’m clearly not objective on that issue). So, I’m not saying that we need less research, but I am saying that there are certain topics that have been so well studied that we should move on and focus our efforts on real questions.

The autism scare is the perfect embodiment of this situation. Anti-vaccine parents continue to insist that we need more research on the link between vaccines and autism, when the reality is that there is no link. Study, after study, after study, after study, after study has failed to find any link between vaccines and autism. In fact, we have dozens of these studies including a massive meta-analysis with over 1.2 million children which failed to find any significant difference in autism rates between the vaccinated and unvaccinated. That is one of the largest sample sizes that I have ever seen, and as a general rule, the larger the sample size, the more certain you can be of the result (I explained the evidence in more detail here).

Now, if you’re an anti-vaccer, you’re probably thinking, “fine, there are studies, but they were all paid for by Big Pharma,” but you’re wrong. Many of those studies (including the meta-analysis) had no conflicts of interest. Further, even a recent study that was funded by an anti-vaccine group failed to find any evidence that vaccines cause autism. Finally, you have to evaluate each paper individually and present actual evidence that they are biased/flawed. You can’t just blindly accuse all of them of being bought off.

In the spirit of openness and honesty, I will acknowledge that if you dig around, you can find a few studies which have suggested that vaccines cause autism, but these are nearly always poorly designed studies that are riddled with problems. Further, most of them are correlation studies that cannot establish causation,  and the few studies that actually made proper comparisons all had tiny sample sizes (you can find details about most of the papers here and here). Sometimes you get false results, just by chance, but the odds of that happening are much lower with larger sample sizes, and when numerous large studies all agree with each other (as is the case for vaccines) it would be absurd to reject them in favor of a handful of tiny, methodologically flawed studies.

My point in all of this is simply that the supposed link between vaccines and autism has been studied so many times by so many researchers that we are extremely confident that the link is imaginary and we should move on. Nevertheless, anti-vaccers continue to insist that we need more studies; therefore, every year more studies on vaccines and autism are conducted, but that’s absurd! We know that vaccines don’t cause autism, but we don’t fully understand what actually causes it (though genetics seem to be important), nor do we know how to cure it or even effectively treat it, not alone prevent it. That is what we should be studying. We should be trying to understand its real cause, and we should be looking for ways to actually help the people that have it rather than pouring money down the toilet looking for an answer that we already have, especially when the group that is demanding the studies is never going to accept the results of those studies. Are we really naive enough to think that study number 100 will convince them when the past 99 haven’t? If a sample size of 1.2 million isn’t enough to persuade you, than nothing will ever be good enough for you. That is why the claim that we need more studies is nearly always hypocritical. You can’t sincerely claim that there aren’t enough studies while simultaneously willfully ignoring all of the studies that we actually have.

Note: I want to be clear that there are many researchers studying the real causes of autism and potential treatments, but my point is that every year money and countless man hours get spent doing yet another study on vaccines and autism, and that time and money would be better spent elsewhere.

If we expand the situation beyond autism, we find the same pattern across vaccine issues. Anti-vaccers ardently insist that there aren’t enough studies despite the fact that there are literally thousands of studies. We’ve looked for relationships between vaccines and SIDS, (Hoffman et al. 1987; Griffin et al. 1988; Mitchell et al. 1995; Fleming et al. 2001; Vennemann et al. 2007a; Vennemann et al. 2007b), asthma (Kramarz et al. 2000; Offit and Hackett 2003Grabenhenrich et al. 2014), allergies (Koppen et al. 2004), general health (Schmitz et al. 2011), etc. You name it, we’ve done it. Vaccines are probably the most well studied topic in medical history, and if you claim that they haven’t been well studied, you are simply displaying your own ignorance.

To be clear, I obviously think that any new vaccines should be rigorously tested before being released to the general public (which they are, btw), and I have no problems with doing research on any novel concerns that arise if that there is good justification for them. However, it is a pointless waste of time and money to continue to study topics for which we already have very clear and well established answers. Further, you absolutely cannot justify opposing vaccines on the basis of a lack of studies because in reality, there is a plethora of studies.

Moving beyond vaccines, we find the exact same story for GMOs. In fact, I personally encounter this argument more often for GMOs than for vaccines. People tell me all the time that we need more research before eating or growing GMOs, but is it really true that they haven’t been properly studied? If you are one of the people who thinks that it is, then let me ask you this: how many studies would be enough to convince you? A few dozen? A few hundred? How about 1,700? Would that be enough? Because we have well over that. This review from 2013 examined 1,783 studies and failed to find any evidence that GMOs are dangerous for us or the environment (Nicolia et al. 2013). Say it with me: there are over 1,700 studies on the safety and environmental impacts of GMOs. Further, several hundred more studies have been conducted since that review, and they have consistently found that GMOs are no worse for us or the environment than traditional crops (in some cases they are better). So please, don’t sit there telling me that we need more studies unless you can also give me a logically and scientifically valid reason why you reject all of the 1,700+ studies that we have already done (you should also check out this massive review looking at the health of livestock before and after the introduction of GMO feed). Also, just to be clear, over half of those studies have no ties (financial or otherwise) to agricultural companies (details and sources here).

Finally, let’s look at climate change. On this topic, people are prone to claim that we don’t have enough evidence to warrant action, but that’s once again absurd. We have extremely clear evidence that we are causing it, and thousands of papers from numerous fields of study have confirmed the results. We carefully tested all of the known drivers of climate change, and no combination of natural factors can explain the current warming. The only way to explain the warming is to include our greenhouse gas emissions in the analyses (Meehl, et al. 2004; Wild et al. 2007; Lockwood and Frohlich 2007, 2008; Lean and Rind 2008; Foster and Rahmstorf 2011; Imbers et al. 2014). More details and sources here,  here, and here.

To be fair, it is true that we don’t know exactly how much we are causing it to change, or exactly what will happen in the future, and we should continue to study those topics; however, we have plenty of data to be extremely confident that our actions are causing the bulk of the current climate change, the changes are already having negative impacts for us, and the changes will continue unless we modify our behavior. On those key points, there is no serious debate among scientists. So the claim that we should wait for more data before we take action is misguided and dangerous. Further, in my experience, this claim is nearly always made by people who completely deny climate change and will never accept the results of any study that opposes their preconceived views. So once again, the claim is disingenuous.

But what if…

At this point, inevitably, someone is getting ready to make a comment along the lines of, “but what if there are things that we missed? What if there is a problem with GMOs, vaccines, etc. that we haven’t found yet? Science isn’t perfect and it is arrogant to think that we know everything.”

I agree that science isn’t perfect, and if scientists actually claimed to know everything, I would agree that they were being arrogant, but they don’t claim to know everything. Rather, they simply make conclusions based on all available evidence, and when that body of evidence is extensive, those conclusions can be reached with a high degree of confidence. Look, it is always possible that we missed something. This is true for absolutely any technology that has ever been tested. As a result, it would always be possible to make this argument. No matter how many studies we’ve conducted, it is still possible that we missed something. Therefore, the only rational approach is to study something up to the point that we are as confident as we ever could be in the conclusion, and for things like the safety of vaccines and genetic engineering, we’re there. In fact, we crossed that line long ago.

Let me ask you this, if around 2,000 studies on GMOs isn’t enough, then what would be? How many studies does it take? There has to come a point at which you acknowledge that we have studied a topic so thoroughly that it is exceedingly unlikely that our conclusions are wrong, and if you ask me, that line occurs long before 2,000 studies.

This is especially true for things like vaccines and GMOs where the known benefits are great. We know, for example, that vaccines save millions of lives each year. So given that known benefit, it makes absolutely no sense to oppose them out of the slight possibility that we’ve missed some unknown danger. For things like climate change, the same concept applies, but the situation is somewhat reversed. In other words, all available evidence shows that the consequences of not acting will be dire, so saying that we shouldn’t take action because of the extremely slight chance that we are wrong is incredibly foolhardy.


In summary, do we need more studies on vaccines, GMOs, climate change, etc.? Yes, of course we do, but we need to be studying the things that are actually unknown rather than pandering to people who will never accept any study that disagrees with their biases and preconceptions. Replication is certainly important in science, and we should try to replicate any important results, but once a result has been consistently corroborated over and over again by numerous studies, we should move on. We should be focusing on how to improve vaccines and make vaccines for more diseases rather than producing yet another study on vaccine and autism. We need more research on making GMOs that provide vitamins and economic benefits to developing countries, and less research on whether or not the fundamental technology is safe. We should continue to study the climate, but we shouldn’t wait for future studies before taking action. In short, we should be studying new and marvelous things rather than repeating something that we have already done hundreds of times in the vain hope that people are actually reasonable and will be willing to change their views when presented with one more study.

Literature Cited

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8 Responses to Do we need more studies on vaccines, GMOs, climate change, etc.?

  1. In the case of climate change, there is the additional motive, as well as justifying unwarranted rejection, that more research would mean more time before action. To quote “Yes Minister” from memory: the civil servant advising the Minister on how to avoid acting on a scientific report, says “Sayscientists disagree. Say more research is needed.” “But is it, and do they?” “Of course. Scientists *always* disagree and there is *always* a need for more research.”

    Liked by 1 person

  2. Reblogged this on Primate's Progress and commented:
    An undefeatable strategy for delaying or doubting. As Sir Humphrey As the Civil Servant Sir Humphrey advised Jim Hacker in Yes, Minister, when he wanted to evade taknig action about smoking, “Ssay the scientists disagree. Say there is a need for more research. Scientists always disagree with each other about something or other, and there is always a need for more research.”


  3. If the denier says that the science isn’t settled, and also wants to take away funding for research, how can the science ever be settled? Then again, consistency or intelligent thought are not their typical strong suits. Categorical denial, no matter the quantity or quality of evidence, is more their speed.


  4. Steve Brügge says:

    Another approach with the anti-vaccine crowd is to ask if they would want to go back to the early 1900s when millions and millions of children died from all the diseases for which we now have vaccines. In the case of smallpox, it’s not even given as a vaccine because it’s eradicated. What parent would choose polio over autism? The choice is obvious even if this imagined risk were real–vaccinate!


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