I think that the interesting thing about vaccine responses has been that over the last two and a half years, it’s been very focused on COVID. With our initial cohort of pediatric MS patients, we’re often testing hepatitis B vaccine response and varicella vaccine response, mostly because we’re starting patients on immunotherapies where we need that testing anyway, so there was a natural cohort of that data available for us to pool...
I think that the interesting thing about vaccine responses has been that over the last two and a half years, it’s been very focused on COVID. With our initial cohort of pediatric MS patients, we’re often testing hepatitis B vaccine response and varicella vaccine response, mostly because we’re starting patients on immunotherapies where we need that testing anyway, so there was a natural cohort of that data available for us to pool.
What we did is we looked at our center, which has a very high number of pediatric MS patients, mostly of Hispanic descent, and then our colleagues at Stanford also collected their data as well, and we kind of pulled it together. I think the results were very surprising to us. We found that only about 40% of individuals with pediatric onset multiple sclerosis were making appropriate vaccine responses to varicella. About 45% were responding to hepatitis B vaccines. In our state in California, we have a registry of children who have been vaccinated, so we actually went back to the original record to make sure that they had been vaccinated according to CDC guidelines and all of them had been.
I think that we’re kind of left with this presumption that there’s… We know that multiple sclerosis is an autoimmune disorder, but is it actually more a disorder of immune regulation, which actually this study seems to kind of raise as a potential possibility as well.
For starting these patients on an immunotherapy, we have to often boost them. I think that was kind of one of our bigger questions is okay, well, we know that they’re not having appropriate vaccine response. What do we do now? To actually get them started on the therapy, we are now boosting them. I think that the bigger question it has raised is, one, should we be screening for this in terms of both the vaccine responses that we’re already checking, but in addition, pneumococcal vaccination, diphtheria vaccination, all of these other things that we don’t tend to think about in otherwise healthy children.
Then, in addition to that, do we need to take this data that we’ve found in non-COVID vaccination and actually start screening for that more closely? Much of the vaccine data and vaccine response data has come in adults. Again, there’s an added wrinkle for our individuals with an autoimmune disorder. Then, certainly our biggest question, I think our biggest safety question long-term is should we be boosting these patients? Should we be relying on T-cell mediated vaccine responses? Because the last thing we want to do is just start giving vaccines under the presumption that, well, they need more of a B-cell response, which could potentially tip these very fragile patients over into a B-cell exhaustion state.