I had a scary reaction to my first and only Pfizer vaccine in late August. It didn't start until later in the day, went all night, then started lessening during the following day. My heart was going BOOM! BOOM! BOOM! really hard and skipping every 3 or 4 beats. The odd thing is that I had exactly that reaction earlier in the summer when I found out that I was allergic to tart cherries. I have several other allergies, including shellfish, latex, and some pollens. I'm trying to think of alternative ways I can get immunized. Wasn't crazy about what I read about the J&J one. If I could I would try the children's one, which is a third the dose of the regular adult Pfizer one. as a test.