A 12-month-old child with no prior immunisation records presents to the clinic. The parents report the child was born at home and never received any vaccines. What is the most appropriate next step in catch-up immunisation?

Explanation

## Catch-Up Immunisation Strategy for Unimmunised Children **Key Point:** Catch-up immunisation follows the principle of "start from current age" with compressed intervals (minimum 4 weeks) rather than restarting from birth schedule. ### Principles of Catch-Up Immunisation 1. **Age-appropriate starting point:** Begin with the vaccine schedule appropriate for the child's current age (12 months in this case) 2. **Compressed intervals:** Use minimum 4-week intervals between doses instead of standard 6-week intervals 3. **Complete primary series first:** Finish all primary doses before administering booster doses 4. **No need to restart:** Do NOT restart from birth schedule — this wastes time and delays protection ### Catch-Up Schedule for This 12-Month-Old (Example) | Dose | Timing | Vaccines | |------|--------|----------| | 1st | Week 0 | DPT-1, IPV-1, Hib-1, PCV-1, OPV-1 | | 2nd | Week 4 | DPT-2, IPV-2, Hib-2, PCV-2, OPV-2 | | 3rd | Week 8 | DPT-3, IPV-3, Hib-3, PCV-3, OPV-3 | | Booster | After 6 months from 3rd | DPT-B, IPV-B, OPV-B | **High-Yield:** The minimum interval of 4 weeks between catch-up doses is a NEET PG favourite. This is shorter than the standard 6-week interval but still maintains immunogenicity. **Clinical Pearl:** Even though the child is 12 months old, they receive the primary series (3 doses) before any booster — age does not exempt them from completing the primary series. **Mnemonic:** **CATCH-UP = Current Age, Then Compressed intervals, Hurry Up Primary series** — start from current age, use 4-week intervals, complete primary series first.