## **Core Concept**
The measles vaccine is a live, attenuated vaccine used to protect against measles, a highly contagious viral disease. The vaccine is often administered in combination with the mumps and rubella vaccines (MMR vaccine). The typical age for measles vaccination is an important consideration for preventing the spread of the disease, especially in areas with low vaccination coverage.

## **Why the Correct Answer is Right**
The measles vaccine is commonly administered to children in two doses: the first dose at 12 to 15 months of age and the second dose at 4 to 6 years of age. This schedule is designed to ensure that a high percentage of the population is immune to measles, thereby preventing outbreaks. The first dose is usually given at 12 months of age because maternal antibodies against measles, which provide protection to infants, typically waning around this time.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not correspond with the typical vaccination schedule for measles.
- **Option B:** This option might seem plausible but does not align with standard vaccination practices for measles.
- **Option D:** This option suggests an age that is not standard for the initial measles vaccination.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the measles vaccine is given at 12-15 months of age as the first dose, with a second dose at 4-6 years. This vaccination schedule is critical for maintaining herd immunity and preventing measles outbreaks. It's also important to note that individuals who have not received the vaccine or have not had measles should consider vaccination to protect against this highly contagious disease.

## **Correct Answer:** . 9 months