When are the two doses of MMR vaccine typically given?

• A. 2 months and 6 months
• B. 12-15 months and 4-6 years
• C. 4-6 years and 11-12 years
• D. 9 and 15 years

Answer: (B)

Two doses of MMR vaccine are given to ensure durable immunity. The first dose is given around 12 to 15 months, when maternal antibodies have waned enough for the vaccine to be effective. The second dose is given at 4 to 6 years to catch children who didn’t respond to the first dose and to boost protection before school entry. This timing aligns with typical pediatric schedules and provides the highest, most reliable protection for measles, mumps, and rubella. Dosing earlier than 12 months isn’t effective due to maternal antibodies, and other suggested timings don’t align with standard routine vaccination windows.