At what age is the first live vaccine, MMR, typically administered?

The first live vaccine for measles, mumps, and rubella (MMR) is typically administered at 12 months of age. This timing is important because the vaccine contains live attenuated (weakened) viruses, and administering it too early can result in suboptimal immune response or interference from maternal antibodies that may still be present in younger infants. By 12 months, most infants have lost these maternal antibodies, allowing for a more effective immunization response.

In general, live attenuated vaccines like MMR are scheduled according to the recommended immunization guidelines, which emphasize giving them when the infant's immune system is adequately developed to handle the vaccine. Therefore, while infants may receive other vaccines earlier in their first year, MMR is specifically given after the age of 12 months.