@ratcatcher I had the two shot Shingrix a few years ago. First shot: nothing notable (basically comparable to DTP/flu/covid booster). Second shot: holy cow, it was like actually being sick (fever, headache, significant fatigue) for about 24 hours, starting a few hours after the shot. I would plan on being as nonfunctioning as one is with a cold for the following day, maybe two.

From what I've seen of people suffering from shingles, it was worth that to avoid shingles later.