In the case of COVID, CDC is emailing all vaccinees every day for a week and then every week for two months to solicit reports.
So, you really can't compare sore arms after COVID to sore arms after tetanus, because COVID reporting is near 100% and tetanus reporting is near zero.
I know a lot of people who got the jab and NOBODY has gotten ANY email from CDC soliciting reports.
And after the first or second one, I bet they all go RIGHT into the spam folder.