How long after receiving the MMR vaccine might a 1-year-old experience a measles-like rash?

A 1-year-old may experience a measles-like rash approximately 1 week after receiving the MMR vaccine. This reaction is generally benign and occurs in a small percentage of vaccine recipients. The vaccine contains live attenuated measles, mumps, and rubella viruses, which can stimulate a mild immune response resembling the natural illness, including a rash.

Typically, this rash appears about 7 to 12 days after vaccination, aligning with the timing indicated in the correct option. It is important for those administering the vaccine and caregivers to be aware of this potential reaction so they can recognize it and reassure families that it is a normal and expected outcome of the vaccination process. Understanding the timing of this side effect enhances awareness of post-vaccination effects, allowing for informed healthcare decisions.