I think vaccines are an interesting therapeutic approach for IBD, but personally I don't feel very optimistic that we'll make it work in the near-term. The website you link to gives an excessively misleading / false impression that MAP is the cause of CD.

There have been a number of whole microbiome sequencing studies comparing IBD/CD patients and healthy controls, and to the best of my knowledge, though there are demonstrable differences, no studies have established or even really "strongly suggested" a causative link with a specific microbe or even with a class of microbes. There are many other candidates that have been found to be associated with IBD, but none of them seem to be to blame on their own. If MAP was the cause of CD, we would easily know it from these studies.

If we knew that MAP was the key, then treatment and prevention would become quite a lot simpler. We simply don't know that, and I'd go so far as to say that this will never work beyond a small subset of patients. IBD (both UC and CD) have a notoriously multifactorial aetiology.