This "experimental" vaccine has been through more testing that many other vaccines most of us have taken.  I wasn't the least bit afraid of taking this one, after receiving 3 of the 5 doses of anthrax vaccine before the DOD said "we're going to push pause on this anthrax vaccine"  (The first of 3 times they did that)... I'm not afraid of much, I haven't developed a 3rd arm from that episode and it's been 20+ years now.  This one got on the street so fast because a lot of the red tape was waived to make it available, not because it wasn't tested.  The only testing not complete would be longer-term effects, which we'd be doing this dance for years if we waited on that.

I'm 41, got my second shot yesterday morning.  The first one my arm was sore as could be for two days, and I was draggy. but can't say it was due to the vax.  Second shot yesterday, tried to use the arm all afternoon and well into the night, and now 24 hours later, just a little soreness in that arm and feel better right now than I have all week.  (Not due to the vax, but worth noting, knock on wood, zero side effect from the second dose.)

Nurse told me that in their local feedback, about 20% of those under 55 were getting some fever and chills after around 12 hours that lasted for 24-36 hours, and another 20% had milder effects, with more than half not reporting anything.  Said the #'s of those with side effects were much lower for over 55 in their region for folks they'd gotten to talk to after the fact.