Dumbass here, and I ask for /sci/s knowledge. I plan to get the JJ vaccine in the coming days, but one thing keeps sticking with me: The fact that most people who get the vaccine claim it "kicks their ass".

I've gotten plenty of vaccines for school and a few flu vaccines, but none of them ever had any effects like that. It gets even more concerning when all the articles about it just hand wave it away and say don't worry about it. Whats the fucking deal?