There is no authoritative information on how long it takes to have no reaction to the MMR vaccine before it is considered safe. Generally, it is considered safe to have no reaction after 6-15 days of the MMR vaccine. The MMR vaccine is mainly used to prevent diseases such as rubella, mumps and measles. Most people will have adverse reactions such as fever, malaise, dizziness, vomiting, and drowsiness within 24 hours after receiving the MMR vaccine. A small number of people will have symptoms such as rash, localized redness, swelling and pain within 6-15 days after having had the MMR vaccine, so patients who have had the MMR vaccine without any uncomfortable reactions within 6-15 days are mostly considered to be safe. Usually, it is safe if there is no adverse reaction within 15 days after the MMR vaccination. It is recommended to observe the vaccination site for half an hour before leaving, and to keep the area clean and dry and avoid touching water after the MMR vaccination. If the discomfort after MMR vaccination is more serious, you need to consult a doctor in time and follow the doctor’s instructions for treatment.