A 12-month-old child from rural India presents for routine immunisation review. According to the National Immunisation Schedule, which is the most common vaccine-preventable disease for which a booster dose is recommended at 12–15 months of age?

Explanation

## Booster Immunisation at 12–15 Months (NIS India) **Key Point:** According to the Indian National Immunisation Schedule (NIS/UIP), the vaccine given specifically as a **booster at 12–15 months** for a single vaccine-preventable disease is **Measles** (as Measles or MR vaccine — second dose/booster). ### Immunisation Schedule at 12–15 Months | Vaccine | Age | Dose | Route | | --- | --- | --- | --- | | Measles / MR (2nd dose) | 12–15 months | 0.5 mL | SC | | Vitamin A (1st dose) | 9 months (with measles) | 1 lakh IU | Oral | | OPV Booster | 16–24 months | 2 drops | Oral | | DPT Booster 1 | 16–24 months | 0.5 mL | IM | **High-Yield:** Per the current Indian NIS (IAP/GOI schedule): - The **first dose of Measles/MR** is given at **9 months** - The **second dose (booster) of Measles/MR** is given at **12–15 months** — this is the defining booster in this age window - DPT Booster 1 and OPV Booster are scheduled at **16–24 months**, NOT 12–15 months - Hepatitis B primary series is completed by 6 months; no booster is scheduled at 12–15 months **Clinical Pearl:** Measles immunity after a single dose is approximately 85–90%; the second dose at 12–15 months ensures seroconversion in primary vaccine failures and is a cornerstone of measles elimination strategy in India (Park's Textbook of Preventive and Social Medicine). **Reference:** Park's Textbook of Preventive and Social Medicine, 27th edition; Government of India Universal Immunisation Programme schedule. **Mnemonic:** **Measles at 12–15** — the second Measles/MR dose is the hallmark booster at 12–15 months in the Indian NIS.