I had a much stronger reaction to the second Moderna jab in mid-May, which some other folks have reported for the mRNA vaccines.
With the first shot I felt some aching and fatigue starting about four hours after the shot, and it lasted for about four hours. I just napped through it and felt fine. It was a bit worse than most of my reactions to annual flu shots, which usually don't cause much reaction.
With the follow up shot the side effects didn't hit until 12 hours later. And the next 12 hours were absolutely miserable. I could understand why some folks swear some vaccines "made them sick." Body aches, headache, dizziness, nausea, etc.
And for the next few weeks I had intermittent days of feeling pretty good and pretty miserable. It was around the second week of June before I began to feel more or less normal. I had continued jogging and cycling throughout, but felt sluggish, like my legs and body refused to respond.
If a stronger reaction is any indication of the quality of the immune response, I must be bulletproof after that mess.