Babies typically receive the first dose of the measles vaccine (as part of the MMR vaccine for measles, mumps, and rubella) between 12 and 15 months of age. The second dose is usually given between 4 and 6 years of age or around school entry. However, in certain situations such as an outbreak or international travel to a measles-affected area, infants can be given the vaccine as early as 6 months old. If a baby receives the vaccine before the first birthday, they should still get two additional doses after turning 12 months old to ensure lasting immunity. In summary:

• Routine first dose: 12 to 15 months old
• Second dose: 4 to 6 years old (or earlier if at least 28 days after the first dose)
• Early vaccination (as early as 6 months) may be given during outbreaks or before international travel, with additional doses following after 12 months.