Well just an update to this from our end. We all had it on Friday. Ashton who is 3.5 immediately went really lethargic and felt really warm although he didn't have a fever. We were still in the doctors rooms when it happened. The doctor said if he didn't pick up to bring him back in. Probably about 5 hours later he started to become more alert. He slept for a while during that time, and by the time he went to bed that night was back to his old self.
So we're not sure if it was just a combination of shock/sore arm/lack of sleep for him, but he has never done that with any other needle. So that was our experience. Both my other boys and myself were fine.
Oh and the doctor had to double check what version he could have. Apparently there is a peadatric one for under 3yr olds. But cause he was over 3 he had the standard one.

