Question: how long do side effects last after mmr?
Answer: The MMR vaccine is very safe. Most side effects are mild and do not last long, such as: the area where the needle goes in looking red, swollen and feeling sore for 2 to 3 days. around 7 to 11 days after the injection, babies or young children may feel a bit unwell or develop a high temperature for about 2 or 3 days.