What diseases does the MMR vaccine prevent?

The measles-mumps-rubella (MMR) vaccine is a combined attenuated live vaccine used to prevent measles, mumps, and rubella. After administration of the MMR vaccine, the child’s immune system is stimulated to produce antibodies against the measles virus, mumps virus, and rubella virus, thereby conferring immunity against these three diseases. MMR vaccination can generally be administered year-round; however, it is not recommended during peak transmission seasons of these diseases. Adverse reactions following MMR vaccination may occur. The most common local reaction is pain and tenderness at the injection site, typically appearing within approximately 24 hours post-vaccination and resolving spontaneously within 2–3 days in most cases. A mild fever may develop within 1–2 days after vaccination, usually lasting 1–2 days and resolving without intervention. During this time, ensure the child drinks adequate fluids. For children with temperatures below 38°C (100.4°F), physical cooling measures are appropriate. Additionally, some children may develop a scattered, non-specific rash 6–12 days after vaccination. This rash typically lasts no more than two days and requires no specific treatment or medical evaluation, as it represents a normal, self-limiting vaccine reaction.