At The World Vaccine Congress in Washington this year we were lucky to meet some of our experts for exclusive insights into their work and the content they were contributing to the event. In this interview we spoke to Dr Christine Stabell Benn from the University of Southern Denmark, who joined us to participate in the Vaccine Safety track with a session on the “non-specific effects of vaccines”. We find out a bit more about this and Dr Stabell Benn’s work, and hope that you enjoy the conversation!
Non-specific effects
We asked Dr Stabell Benn what the term “non-specific effects” means, and what we know about them in the context of vaccines. She explains that it’s a “relatively new concept within vaccinology”. While we understand that vaccines induce “specific protective effects” as well as, in rare cases, some adverse events or responses, what Dr Stabell Benn and her team have identified is that “vaccines have effects on the risk of dying from infectious diseases that simply cannot be explained just based on their specific protective effect against the vaccine disease”.
Dr Stabell Benn considers the example of introducing the measles vaccine to a “naïve community” and finding that in the first year mortality “declined by 70%”. This is “much more than explained” by the prevention of measles.
“What happened was this incredibly large effect, which then led to the hypothesis that measles vaccine has these beneficial non-specific effects. It strengthened the general immune system and its ability to respond to a broad range of pathogens and basically acts as a shield towards dying from a lot of different infections.”
Putting this to the test
With the hypothesis in mind, we asked about any trials or investigations to understand these effects. Dr Stabell Benn states that she is “consistently going through all the routine vaccines that are in use” and “looking for their effect on overall mortality and morbidity”.
“For all the vaccines we’ve studied, and that’s ten now, we have seen that they have these non-specific effects.”
Returning to the measles example, Dr Stabell Benn has pushed her ideas forward through trials, including randomised control trials, which is “challenging”:
“When you’re talking about routine vaccines, you have to think of the science where you don’t deprive a child of a vaccine, and preferably also don’t delay it.”
Thus, it can be helpful to “manipulate” the schedule to enable randomised comparisons.
Different contexts
Our next question goes back to the subject of Dr Stabell Benn’s session, which considered these non-specific effects in different settings. She explains that, as the “very strong effects of vaccines” emerged in lower-resource settings, the question of how they might emerge in higher-income settings was raised. With the childhood mortality rates in these contexts being “so low”, it would be hard to study this in the same way. Therefore, risk of hospitalisation can be used as a marker.
In the US context, Dr Stabell Benn refers to an investigation into the difference between live-attenuated vaccines and non-live vaccines:
“Children, depending on whether they had a live or a non-live vaccine as their most recent vaccine had a very different risk of getting hospitalised for infectious diseases. So those that had a live vaccine as their most recent vaccine had a 50% lower risk of getting hospitalised for any infection in the follow-up period.”
Dr Stabell Benn believes that this “immune training” from live-attenuated vaccines seems to be “consistent across the world”.
Why WVC?
With all of our interviewees we ask about their intentions or expectations of the event. For Dr Stabell Benn, the goal is to “get more people aware” of her work on non-specific effects.
“The whole system for both deciding vaccination programmes and also for testing and approving and regulating vaccines, they haven’t adopted these findings.”
Alongside her mission to spread awareness, Dr Stabell Benn hoped to learn and connect with her colleagues.
“What I feel I do here is bring a new perspective…I can feel sometimes there isn’t a lot of room for it…It’s fun; it’s challenging, to be in a setting with a new kind of knowledge, a different kind of knowledge.”
It was fantastic to hear from Dr Stabell Benn and we hope that you enjoy watching her interview. If you’d like to learn more do check out her 2018 Ted Talk here or visit her team’s site here!
For more conversations with our experts from the Congress in April do make sure you subscribe for weekly updates here!
