The MMR vaccine is a combined vaccine that protects against measles, mumps, and rubella, three highly contagious viral diseases that once caused millions of infections, hospitalisations, and deaths worldwide. In the United States, children are typically given the first dose at 12–15 months of age and a second dose at 4–6 years, while many countries, including India, follow similar schedules through their national immunisation programmes. The vaccine is administered to prevent serious complications such as pneumonia, brain swelling (encephalitis), deafness, birth defects, and pregnancy-related complications caused by rubella infection.
