Covid vaccine: Sore arm and headache most common side effects
News from the BBC
The most common side effects of the Covid-19 vaccines are pain or tenderness at the injection site - in other words, a sore arm - a UK study has suggested.
Roughly one in four people had wider effects like fever, headache, nausea and fatigue.
But these only lasted on average for one day.
Researchers involved in the ZOE Covid Symptom Study app saw fewer reactions than were seen in clinical trials.