Scientists Question Safety of Vaccines (WHO Global Vaccine Safety Summit December 2019)
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Summary
In this episode, Dr. Hans and Marianne discuss the dangers of adding adjuvants to vaccines and how to prevent them. They discuss the benefits of avoiding them, the risks of adding them, and what to look out for when using them.
Transcript
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And without the good science, we can't have good communication.
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So although I'm talking about all these other contextual issues and communication issues,
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it absolutely needs the science as the backbone.
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You can't repurpose the same old science to make it sound better
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if you don't have the science that's relevant to the new problem.
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So we need much more investment in safety science.
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I think we cannot overemphasize the fact that we really don't have very good safety monitoring systems in many countries.
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And this adds to the miscommunication and the misapprehensions
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because we're not able to give clear-cut answers.
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When people ask questions about the deaths that have occurred due to a particular vaccine,
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one should be able to give a very factual account of what exactly has happened and what the cause of deaths are.
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But in most cases, there's some obfuscation at that level,
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and therefore there's less and less trust then in the system.
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Every time that there is an association, be it temporal or not temporal,
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And yet without adjuvants, we are not going to have the next generation of vaccines.
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And many of the vaccines that we do have, ranging from tetanus through to HPV,
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So the challenge that we have in front of us is how do we build confidence in this?
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And the confidence, first of all, comes from the regulatory agencies.
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When we add an adjuvant, it's because it is essential.
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We do not add adjuvants to vaccines because we want to do so.
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But when we add them, it adds to the complexity.
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And I give courses every year on how do you develop vaccines, how do you make vaccines.
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And the first lesson is, while you're making your vaccine,
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if you can avoid using an adjuvant, please do so.
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Lesson two is, if you're going to use an adjuvant, use one that has a history of safety.
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And lesson three is, if you're not going to do that, think very carefully.
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It seems to me that adjuvants multiply the immunogenicity of the antigens that they are added to.
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It seems to me they multiply the reactogenicity in many instances.
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And therefore, it seems to me that it is not unexpected if they multiply the incidence of adverse reactions
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that are associated with the antigen, but may not have been detected through lack of statistical power in the original studies.
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As we add adjuvants, especially some of the more recent adjuvants, such as the ASO1, sapin, and derived adjuvants,
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The primary concern, though, usually is systemic adverse events rather than local adverse events.
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And we tend to get, in the phase two and the phase three studies, quite good data on the local reactogenicity.
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Those of us in this room that are beyond the age of 50 who have had the pleasure of having the recent shingles vaccine
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will know that this does have quite significant local reactogenicity.
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If you got the vaccine, you know that you got the vaccine.
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The major health concern which we are seeing are accusations of long-term effects.
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So to come back to this, I'm going to once again point to the regulators.
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It comes down to ensuring that we conduct the phase two and the phase three studies with adequate size
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So in our clinical trials, we are actually using relatively small sample sizes.
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And when we do that, we're at risk of tyranny of small numbers,
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which is you just need a single case of Wegner's granulomatosis,
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and your vaccine has to solve Walt's how do you prove a null hypothesis.
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And it takes years and years to try to figure that out.
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So it's a real conundrum, right, getting the right size, dealing with the tyranny of small numbers,
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And so I think one of the things that we really need to invest in are kind of better biomarkers,
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better mechanistic understanding of how these things work
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so we can better understand adverse events as they come up.
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One of the additional issues that complicates safety evaluation is if you look at and you struggle
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with the length of follow-up that should be adequate in a, let's say, pre-licensure
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or even post-marketing study, if that's even possible.
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And again, as you mentioned, pre-licensure clinical trials may not be powered enough.
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It's also the subject population that you administer the R2-1 to,
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because we've seen data presented to us where an adjuvant, a particular adjuvant,
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added to a vaccine antigen did really nothing when administered to a certain population,
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and it's usually the elderly, you know, compared to administering the same formulation to younger age strata.
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So these are things which need to be considered as well
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and further complicate safety and effectiveness evaluation of adjuvants combined with vaccine antigens.
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I cast back my mind to our situation in Nigeria,
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a child is being given different antigens from different companies,
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and these vaccines have different adjuvants, different preservatives, and so on.
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Is there a possibility of these adjuvant preservatives cross-reacting amongst themselves?
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Have there ever been a study on the possibility of cross-reactions from the panel members
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Now, the only way to tease that out is if you have a large population database,
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like the Vaccine Safety Data Link, as well as some of the other national databases that are coming to being,
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where the actual vaccine exposure is tracked down to that level of specificity
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of who is the manufacturer, what is the lot number, et cetera, et cetera.
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And there's an initiative to try to make the vaccine label information barcoded
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so that it includes that level of information so that in the future,
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when we do these type of studies, we're able to tease that out.
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then the sample size gets becoming more and more challenging,
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and that's what I said earlier today about that we're really only in the beginning
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of the era of large data sets where hopefully you could start to kind of harmonize the databases
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for multiple studies, and there's actually an initiative underway.
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Helen there may want to comment on it to try to get more national vaccine safety database linked together
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so we could start to answer these type of questions that you just raised.
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The other thing that's a trend and an issue is not just confidence in providers,
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We have a very wobbly health professional front line
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that is starting to question vaccines and the safety of vaccines.
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When the front line professionals are starting to question
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or they don't feel like they have enough confidence about the safety
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to stand up to it to the person asking them the questions.
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I mean, most medical school curriculums, even nursing curriculums,
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I mean, in medical school, you're lucky if you have a half day on vaccines,