Ah, well, shame you've forgotten why -- I hope you can see that the reason makes a big difference, especially as the two alternatives you've offered are radically different. If the second one, then arguably your doctor predicted the Wakefield effect, etc (ie, people being duped into believing what he was saying while forgetting the dangers of Measles).
On the other hand, if the first, then... I don't understand for a second what he would be trying to say. There's not a shred of credible evidence that vaccines suppress the immune system; indeed, the exact opposite is, by definition true: they enhance the immune system (albeit with the need for a couple of booster jabs later).
See, for example,
https://tinyurl.com/y9scdfqc , which is a review of the evidence (or rather, the lack of it) for links between vaccination programmes and weakened immune systems.