Question

At what age is the first dose of measles vaccination given?

• A. 9 months
• B. At birth
• C. 4 weeks
• D. 8 weeks

Hint:

Wait until maternal antibodies decline but before natural measles strikes.

Answer 1

The Correct Option is A

Step 1: The timing of measles vaccine is set by when maternal antibodies wane. Antibodies passed from the mother protect the infant for the first few months but also neutralise live vaccine virus, so vaccinating too early gives a poor response.

Step 2: By about 9 months, maternal antibody levels have fallen enough for the live attenuated measles vaccine to take, while the baby is still at high risk of natural measles. Hence the WHO Expanded Programme on Immunization recommends the first dose at 9 months of age.

Step 3: A second dose is given later, at 16 to 24 months, under the National Immunization Schedule, to cover children who failed to seroconvert the first time.

Step 4: The other options are too early. Birth, 4 weeks and 8 weeks all fall within the window of high maternal antibody and would blunt the vaccine response, so 9 months is correct.