A child who has not been vaccinated with H. influenzae comes to the OPD at 14 months. How many doses, including booster would you like to give to this child?
**Core Concept**
The child requires vaccination against *Haemophilus influenzae* type b (Hib), a bacterium that causes invasive disease, particularly meningitis and epiglottitis, in unvaccinated children. The Hib vaccine is a conjugate vaccine that provides immunity by inducing antibodies against the Hib polysaccharide capsule.
**Why the Correct Answer is Right**
The Hib vaccine is administered as a series of doses, with the primary series consisting of 3 doses, followed by a booster dose. The primary series is usually completed by 12-18 months of age. The booster dose is given to provide long-term immunity and is typically administered at 12-15 months of age. In this case, the child is 14 months old and has not been vaccinated, so the recommended course of action is to complete the primary series with 2 additional doses and administer a booster dose.
**Why Each Wrong Option is Incorrect**
**Option A:** This answer is incorrect because it does not account for the primary series of 3 doses and the booster dose required for long-term immunity.
**Option B:** This answer is incorrect because it does not provide enough information to determine the exact number of doses required.
**Option C:** This answer is incorrect because it does not take into account the booster dose required for long-term immunity.
**Clinical Pearl / High-Yield Fact**
The Hib vaccine is a conjugate vaccine that provides immunity by inducing antibodies against the Hib polysaccharide capsule. It is typically administered as a series of 3 doses, followed by a booster dose, to ensure long-term immunity against invasive Hib disease.
**Correct Answer: D. 5 doses, including booster.**