I thought about including my age and am happy to reveal - I'm latter half of mid-30s, male. I imagine the vector vaccine is also prompting an immune response, perhaps compounding the side effects.
Interestingly, I read through some of the study protocol and the site vaccine administrator actually doses the syringe with either locally sourced saline or from the vaccine vial, based on the randomization software's output; they are not blinded. I had no interaction with the vaccine administrator other than to receive the injection. This process may be common for studies but I would have thought everyone at the site was blinded.
Yes, I believe most of the phase III COVID-19 vaccine trials are single blinded. I guess this is to reduce costs of preparing a comparable placebo, which for deep-frozen mRNA candidates could be substantial. It shouldn't affect outcomes as long as there is no conferring between vaccine administrator and participant and I am sure they have been emphatically told they must not do this.