**Core Concept**
Rubella vaccine is a live, attenuated vaccine designed to prevent rubella infection, a viral illness that can cause congenital rubella syndrome in pregnant women. The vaccine is typically administered as part of a combined measles, mumps, and rubella (MMR) vaccine.

**Why the Correct Answer is Right**
The MMR vaccine is recommended for children aged 12-15 months, with a second dose administered at 4-6 years of age. This schedule allows for early protection against measles and rubella, while also providing long-term immunity against these diseases. The rubella vaccine is particularly important for preventing congenital rubella syndrome, which can occur when a pregnant woman contracts the virus and passes it to her fetus.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the MMR vaccine is not typically given at birth or in the first few weeks of life.
**Option B:** This option is incorrect because the rubella vaccine is not usually administered to adults or older children as a standalone vaccine.
**Option C:** This option is incorrect because the MMR vaccine is not given in early childhood, but rather in the first two years of life.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the MMR vaccine is a live, attenuated vaccine, which means it contains a weakened form of the virus. As a result, individuals with compromised immune systems, such as those with HIV/AIDS or taking immunosuppressive medications, should not receive the MMR vaccine.

**Correct Answer: C. 1-2 years.