Some adverse reactions to Moderna and Pfizer vaccines:
https://www.nytimes.com/2020/12/16/h...-reaction.html
https://jamanetwork.com/journals/jam...rticle/2773790 - note percentages of side-effects
https://www.cdc.gov/coronavirus/2019...onditions.html - know your medical history beforehand
This is probably partly due to pushing these out before fully completing clinical trials.
My lab-mates at Gilead are saying they're going to fine-tune their vaccine and have it fully-tested before releasing.