Just to be clear, we are not recommending this. But it is an interesting question – what would happen if someone were vaccinated multiple times, far exceeding standard recommendations, against SARS-CoV2? Well, The Lancet recently reported on a 62 year old gentleman who claims to have been vaccinated 217 times over the last two years. He acquired these vaccines privately for his own purposes. Public records were able to confirm 130 of these vaccinations (which were the mRNA vaccines), while he had personal records of 108 vaccinations with partial overlap.
The two obvious general questions (well, I guess other than why did he do it) are – was this hypervaccination safe, and did it provide extra protection? Let’s take the safety question first. The man, referred to as HIM in the Lancet article, reported no side effects. He did not appear to suffer any medical issues during this time. Also, “62 routine clinical chemistry parameters showed no abnormalities.”
This means that he did not suffer kidney or liver damage, did not experience significant muscle breakdown, and did not develop an auto-immune disease. We cannot rule out at this time a delayed effect or long term risk of hypervaccination with an mRNA vaccine against SARS-CoV2, but any serious side effect is unlikely if there is no sign of any issue after two years.
The researchers who were allowed to examine HIM were most interested, however, in what the effects of hypervaccination were on his immune response. Specifically, did this result in super-immunity, but also did hypervaccination cause exhaustion of his immune system through overstimulation?
On the first question they report:
“HIM’s serum neutralisation capacity was 5·4-fold and 11·5-fold higher compared with the control group vaccinees, for wildtype and Omicron B1.1.529 spike proteins, respectively.”
As expected, repeated vaccination did produce higher antibody levels to the spike proteins, which are the targets of vaccination. Of note, he had detectable levels of antibodies in his saliva, while the control group of vaccinees did not. He also showed higher absolute numbers of memory and effector T-cells. Therefore both humoral and cellular immunity were increased compared to those who followed standard vaccination.
One of the main questions for the researchers was whether or not HIMs immune system would have a decreased capacity to respond to a new antigen challenge (whether from infection or vaccination) because he had essentially exhausted his immune system from repeated vaccination. They had the opportunity to measure this, because HIM continued to receive further vaccinations during the study.
They found no evidence of immune exhaustion. His adaptive immune response appeared to be intact, without any qualitative change. He continued to have an increase in his antibody levels with further vaccination, although these were predictably modest.
It is also interesting to note that antibody testing showed that HIM was likely never infected with SARS-CoV2. Of course, in a single case we cannot attribute this causally to the vaccinations.
What does all of this tell us? We cannot really generalize from a single case like this, but it does show, at least in this one person, that multiple repeated vaccinations with an mRNA vaccine can be entirely safe. There isn’t necessarily any toxicity that kicks in at high doses at this level. Further, the mRNA COVID vaccines he received did not overstimulate or exhaust his immune system, which retained its ability to react to new challenges with intact adaptive immunity.
While again this one case cannot put these questions to bed, it is interesting evidence against many of the claims of anti-vaxxers, who have claimed without evidence that too many vaccines are dangerous and that they overwhelm the immune system.
These claims were never very plausible. Our immune systems are assailed on a daily basis with countless antigens (substances that cause an immune response). Even a complete vaccine schedule represents a tiny additional challenge – insignificant compared to the background workout our immune systems regularly experience. This case study is at least compatible with the standard scientific view, and did not present any surprises.
As an aside, this kind of evidence is frequently used in medicine – case studies or case series of individuals who had exposures that would be unethical to deliver deliberately. Sometimes people, for example, accidentally or deliberately overdose with a pharmaceutical, something we could never do to a person for a study. But it does provide the opportunity to gather data about such high doses. Almost all of our safety data with drugs in pregnancy comes from cases in which women were exposed before realizing they were pregnant, or who ignored standard advice.
So while we have to emphasize that no one is recommending hypervaccination and we cannot be confident that in the general population such hypervaccination is safe, HIM does provide some reassurance. Finally, we need to remember that medicine is always about risk vs benefit. The standard vaccine recommendation are based on this reasoning – how many vaccines are necessary to provide sufficient benefit? Beyond some point you get diminishing returns of benefit with increasing probability of risk. HIM was way past that point.