RFK Jr and vaccine safety – using a bad study to come to bad conclusions

RFK Jr and vaccine safety – using a bad study to come to bad conclusions

Yesterday, Dorit Rubinstein Reiss explained why most experienced journalists ignore Robert F. Kennedy Jr’s views on vaccines. He gets simple facts about vaccines completely wrong again and again. She was referencing an interview Kennedy had given on Fox News – as a part of that interview, Kennedy misused a small study about the DTaP vaccine (for diphtheria, tetanus and pertussis, or whooping cough). Unfortunately, RFK Jr and vaccine safety of DTaP has continued – he has doubled down on misusing this study in an article by him published today.

I thought we would take a look at the issues specific to this new version of RFK Jr and vaccine safety – we’ll analyze his comments and then take a detailed look at the published article that forms the basis of Kennedy’s comments.


RFK Jr and vaccine safety – the article

RFK Jr’s article about vaccine safety was published in Collective Evolution, a pseudoscience-pushing website that has articles about the sun exploding soon and aliens circling the moon. No, I’m not joking, Kennedy thinks his outlandish claims about vaccines fit well next to an article about alien structures on the moon.

But let’s get to what he’s saying about the DTaP vaccine:

Now a team of Scandinavian scientists has conducted such a study and the results are alarming. That study, funded in part by the Danish government and lead by Dr. Soren Wengel Mogensen, was published in January in EBioMedicine. Mogensen and his team of scientists found that African children inoculated with the DTP (diphtheria, tetanus and pertussis) vaccine, during the early 1980s had a 5-10 times greater mortality than their unvaccinated peers.

In the primary analysis, DTP-vaccinated infants experienced mortalities five times greater than DTP-unvaccinated infants. Mortalities to vaccinated girls were 9.98 times those among females in the unvaccinated control group, while mortalities to vaccinated boys were 3.93 times the controls. Oddly, the scientists found that children receiving the oral polio vaccine simultaneously with DTP fared much better than children who did not. The OPV vaccine appeared to modify the negative effect of the DTP vaccine, reducing mortalities to 3.52 times those experienced among the control group.  Overall, mortalities among vaccinated children were 10 times the control group when children received only the DTP.

The data suggest that, while the vaccine protects against infection from those three bacteria, it makes children more susceptible to dying from other causes.

If this were true, it would be one scary study. However, does this study actually make that claim? Stay tuned, we’ll get to it.

Kennedy, then, comes to this conclusion:

In 2014, The World Health Organization (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) conducted its own literature review of the potential non-specific effects (NSEs) of several vaccines, including DTP, and found that the majority of studies reported a detrimental effect of DTP (Higgins et al., 2014; Strategic Advisory Group of Experts of Immunization, 2014) due to its penchant for increasing susceptibility to unrelated infections. SAGE recommended further research.

Moreover, Mogensen and his colleagues observe that the studies reviewed by SAGE probably underestimated the lethal effect of the DTP vaccine because of unusually high mortality in the control groups, ”Unvaccinated children in these studies have usually been frail children too sick or malnourished to get vaccinated and the studies may therefore have underestimated the negative effect of DTP”. The Mogensen study sought to avoid this pitfall by using controls selected by birthday and by eliminating underweight children and orphans from both the study group and the control group. It included only children who were breastfed. All the infants were healthy at the time of vaccination. Nevertheless, the Mogensen authors point out that, even in their study, the unvaccinated children had slightly worse nutritional status and travelled more – biases that would tend to increase mortality. They conclude that, “The estimate from the natural experiment may therefore still be conservative.”

In fact, this is what SAGE says about the pertussis vaccine (a component of DTP) safety (pdf):

Evidence supports a high degree of confidence in the estimate of the effect that incidence of serious adverse events following whole cell pertussis vaccination is low. From the reviewed articles, there is no significant risk of serious adverse events following administration of wP (see Note 1).

This is what SAGE says about the diphtheria component (pdf):

Diphtheria toxoid (see Note 2) is one of the safest vaccines available. Severe reactions are rare, and to date no anaphylactic reac- tions attributable to the diphtheria component have been described.

Finally, this is what SAGE says about the tetanus component (pdf):

Severe adverse events are extremely rare. TTCV using various presentations have demonstrated to be safe to use in immunocompetent individuals of various age and population groups including infants, children, adolescents, adults and pregnant women.

In other words, SAGE has never said that there’s a detrimental effect of the DTP (or DTaP) vaccine on children, adults, or anyone. In summary, SAGE has been very positive, with regards to vaccine safety and adverse events, not even close to the narrative pushed by Robert F Kennedy Jr.

But let’s take a look at this Danish study pushed by RFK Jr.


RFK Jr and vaccine safety – the study

The study, published in EBioMedicine, by Dr. Soren Wengel Mogensen et al. studied the mortality rate of children after vaccination with DTP from 1984-1987. The children received the vaccine during quarterly weigh-ins in Guinea, Africa. Here are some of the issues with the study:

  1. It was published in a rather obscure journal. This alone does not give us an indicator of the quality of the paper, but if we really had data that showed us there was a concern with the DTaP vaccine, an important part of the childhood vaccine schedule, it should have been published in a higher quality journal, maybe one that focuses on vaccines, such as the journal Vaccine. Generally, I have found that publishing in obscure journals results from not finding a place in a major journal, mostly as a result of the weakness of the data.
  2. The study looks at the mortality rate after the vaccine used at that time, which, as I mentioned, contained the whole-cell version of pertussis. That vaccine was pulled from the market and replaced with the acellular version. The reasons for changing the vaccines are complex, but it was partially because of the higher rate of minor adverse events with the wP version of the pertussis vaccine. On the other hand, there is no evidence that the wP version caused more deaths than the current aP version.
  3. The study only examined 1057 children, which is a tiny number in any epidemiological study that tries to compare one group to another to examine a potential effect. Many case control studies that examine vaccine effects (either effectiveness or adverse events) use 100,000 to several million patients.
  4. The number of deaths that was used in the study was tiny, sometimes only 1 death in a population group (like female unvaccinated children). Because they used such small numbers, unintentional bias could occur.
  5. The deaths were not categorized. Were they auto accidents, violence, or other mortality events that absolutely have nothing to do with vaccination. With such small numbers analyzed, it’s possible that unrelated mortality could have given results that could change dramatically with just a handful of unrelated deaths. Unless you can convince me that vehicle mortality is somehow related to vaccination status.
  6. Ironically, the study showed that there was decreased mortality with the children who received oral polio vaccine (separate from the DTP vaccine). If we accept this statistically suspect small sample as unbiased (which we can’t), the overall results are positive with a full vaccination. It kind of contradicts the RFK Jr and vaccine safety narrative.

It’s difficult for me to accept the viability of this study on just about any level. At best, at the very best, we can accept this study as an observational one which could, if not contradicted by better studies, form the basis of a hypothesis about the DTaP vaccine.

And that leads me to another critical point. Robert F Kennedy Jr cherry-picked a study that supports his beliefs about vaccine safety, the antithesis of real science (hence, Kennedy chose the pseudoscientific Collective Evolution for his article). If we look at larger studies more broadly, what can we say about the safety profile of the DTaP vaccine?

Here’s a Danish study that included over 805,000 children looking at various outcomes to getting multiple antigen vaccines, such as DTP or DTaP, came to this conclusion:

These results do not support the hypotheses that multiple-antigen vaccines or aggregated vaccine exposure increase the risk of nontargeted infectious disease hospitalization.

In plain speak, there is no data to support RFK Jr and vaccine safety issues – with respect to these vaccines, there was no difference in non-targeted (that is non-diphtheria, -pertussis or -tetanus) infections in the vaccinated vs. non vaccinated groups. This is much more robust data than the study upon which Kennedy relies for his belief set.

But there’s more. In a meta-review, considered the pinnacle of high quality scientific research hierarchy, which included over 183,000 participants in 58 different trials, the authors concluded that,

Acellular vaccines have fewer adverse effects than whole-cell vaccines for the primary series as well as for booster doses.

Thus, the authors found no vaccine related mortality for either vaccine, which completely and utterly contradicts Kennedy’s belief about the safety of the DTaP vaccine. If we’re going to cherry pick, let’s choose the studies that actually are well designed with good statistics and outcomes that can reject or accept a hypothesis. Kennedy’s study does neither.



Not only does RFK Jr use research that has no relevance to the modern DTaP vaccine, but also he relies on a weak, small, and poorly designed study. Furthermore, the study he uses is clearly of lower quality than other, more powerful and robust studies, which show that there is no mortality concerns with the vaccine.

Kennedy’s cherry picked study simply fails to provide us with any quality evidence that we should be concerned about the modern DTaP vaccine. None. Only in a world of pseudoscience, where a weak, one-off study has more value than better designed and populated studies, can we cherry pick bad evidence to dismiss one of the most useful vaccines in the armamentarium of diseases preventing weapons.

RFK Jr and vaccine safety? Yeah, he’s wrong. Badly wrong.



  1. wP, or whole cell pertussis vaccine, is no longer used in the USA. We use aP, or acellular pertussis, in our DTaP vaccine. At the time of the vaccination of the children in the study, the whole cell version was used.
  2. The diphtheria vaccine doesn’t protect directly against the bacterial infection but against the toxin produced by the diphtheria bacteria which causes the symptoms of the infection.



The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!