COVID vaccines can have side effects, but the vast majority are very short term, and not serious or dangerous. The Vaccine Adverse Event Reporting System (VAERS) collects required reports from healthcare professionals and the public on negative outcomes after a vaccination, whether caused by the vaccination or not.
From these reports and the numerous studies around the world, it’s clear that some people experience pain where they were injected, body aches, headaches, or fever, lasting for a day or two. These are signs that the vaccine is working to stimulate your immune system.
If symptoms persist beyond two days, you should call your doctor. If you have a pre-existing condition, or if you have severe allergies — especially ones that require you to carry an EpiPen — discuss the COVID vaccine with your doctor, who can assess your risk and provide more information about if and how you can get vaccinated safely.
For current data on the vaccines and their possible side effects, please refer to the CDC’s Adverse Events After COVID-19 Vaccination report at https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/adverse-events.html.
SOURCE: https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/covid-19-vaccines-myth-versus-fact (Johns Hopkins Medicine)