That's the downside of operation warp speed, don't have enough time to assess the long-term effects.

All true, but you're assuming that only an mRNA molecule coding for the CV19 antigen is in the vaccine. It could be coding for another self-similar antigen to which our immune systems could produce antibodies to gradually attack a specific tissue (eg. reproductive system or some neural tissues specializing expressing certain neuro-transmitters). Think beta hemolytic streptococcus antibody's impact on heart muscle