I'm 71 and received the Moderna vaccine. After the first shot I had a minor increase in pain, however, with the second shot I really reacted. Intense leg pains kept me up all night and the entire next day. Add to that entire body aches, chills, and a strange headache and I felt pretty punk. After a relatively "good" night sleep the 2nd night, I awoke all back to normal. One and a half days down but all worth it! Everyone has a different immune system though and only about 25% react significantly to the second vaccine (if I recall the figure correctly).