Reported side effects to COVID-19 vaccines have mostly been mild to moderate and short-lasting. They include:
fever
fatigue
headache
muscle pain
chills
diarrhoea
pain at the injection site
The chances of any of these side effects following vaccination differ according to the specific COVID-19 vaccine.
More serious or long-lasting side effects to vaccines are possible but extremely rare. Vaccines are continually monitored to detect rare adverse events.