Well, I'm the youngest of our group that got it and I'm 50. The older folks all had arm pain for days. We had a lot of grumpy folks on a video call three days later.
Nocebo effect is proven for vaccines. Even if we inject salted water: many will develop fevers, arm pain, headaches, nausea, ... (because they expect such symptoms). In some cases, as many as 90% of observed side effects are nocebo. i.e. if 100 people get the real vaccine and 100 people get salted water, 10 will get side effects on the first group, 9 will get the same side effects on the control group.
