I'm not sure how much it would mess up their sense of taste or smell etc, but I think the biggest risk of the oral vaccine as opposed to the injection is that they can bring it up again if they posset, and in that case they would not get the full effect of the vaccine and they can't have it again JIC. So for that reason I would go for the needle, especially if you are adamant you want bubs to have it. You can minimise the 'trauma' they experience if you are BF bubs at the time it is done.

Also some hospitals don't carry the oral vaccine, so it's something you would have to ask them beforehand JIC they don't have it