During an immunisation outreach camp in a slum area of Delhi, an ANM encounters a 9-month-old child who has received only BCG and OPV-0 at birth, with no subsequent doses. The child is clinically well with no fever or signs of acute illness. The mother reports that she was unaware of the immunisation schedule and missed all previous appointments. What is the most appropriate next step?

Explanation

## Catch-Up Immunisation Strategy in UIP ### Clinical Scenario Analysis A 9-month-old child with **no immunisation history** (except BCG and OPV-0 at birth) presents for immunisation. The child is well with no contraindications. **Key Point:** The UIP follows a **catch-up, not restart** principle. The child should receive the **next due dose in the sequence**, regardless of age, and then proceed through the schedule at standard intervals (4 weeks between doses). ### Correct Approach: Sequential Catch-Up **High-Yield:** At 9 months, the child is due for: - **DPT-1** (first dose of primary series) - **OPV-1** (first dose of primary series) - **Hepatitis B-1** (if not given at birth; part of UIP) These vaccines should be administered **immediately** in a single visit, and subsequent doses scheduled at **4-week intervals**. ### UIP Immunisation Schedule (Catch-Up Approach) | Age at Visit | Next Due Doses | Interval to Next Dose | |---|---|---| | 9 months (missed 6, 10, 14 weeks) | DPT-1, OPV-1, HepB-1 | 4 weeks | | 13 months (9 + 4 weeks) | DPT-2, OPV-2, HepB-2 | 4 weeks | | 17 months (13 + 4 weeks) | DPT-3, OPV-3, HepB-3 | — | | 18 months | DPT Booster-1, OPV Booster | — | **Clinical Pearl:** The principle of **"start where you are, not where you should be"** is central to UIP catch-up strategy. This maximizes coverage in resource-limited settings and reduces the burden of missed appointments. ### Why Administer Multiple Vaccines in One Visit? 1. **Safe:** Multiple vaccines can be co-administered at different sites without reducing immunogenicity or increasing adverse events. 2. **Improves compliance:** Reduces the number of visits required. 3. **Reduces disease risk:** Accelerates protection against vaccine-preventable diseases. 4. **Follows WHO/UIP guidelines:** Catch-up immunisation is designed to be efficient and pragmatic. ### Spacing Between Doses - **Minimum interval between doses:** 4 weeks (28 days) - **No maximum interval:** If a dose is delayed, the next dose is given as soon as possible without restarting the series - **Multiple vaccines:** Can be given simultaneously at different injection sites **Mnemonic:** **CATCH-UP** = **C**ontinue from next due dose, **A**dminister immediately, **T**hen schedule at 4-week intervals, **C**o-administer safe vaccines, **H**ighest priority is protection, **U**se standard sites, **P**roceed without restart. [cite:Park 26e Ch 8]