A 4-month-old female infant from Delhi presents to the immunization clinic for her routine vaccination. She was born at 34 weeks gestation (weight 1.8 kg at birth) and is now 4 months chronological age (2 months corrected age). On examination, she weighs 3.2 kg and appears clinically well. Her mother reports that the infant developed a low-grade fever (38.1°C) and mild local swelling at the injection site 6 hours after her previous DPT dose 2 weeks ago, which resolved within 24 hours. Today, her temperature is 37.0°C and she is afebrile. The child is due for her second dose of DPT vaccine. Which of the following is the most appropriate management?

Explanation

## Mild AEFI and Continuation of Vaccination **Key Point:** Mild fever and mild local reactions (redness, swelling <2.5 cm) following DPT vaccination are expected adverse events and are NOT contraindications to subsequent doses. Vaccination should proceed as scheduled. ### Classification of Adverse Events Following Immunization (AEFI) | Severity | Local Reaction | Systemic Reaction | Vaccination Decision | |----------|---|---|---| | **Mild** | Swelling/redness <2.5 cm | Fever ≤38.5°C, mild irritability | Continue vaccination | | **Moderate** | Swelling/redness 2.5–10 cm | Fever 38.6–39.5°C, persistent crying | Continue vaccination | | **Severe** | Swelling >10 cm, abscess | Fever >39.5°C, seizures, anaphylaxis | Assess contraindication; may defer or modify | **High-Yield:** The distinction between AEFI and true contraindication is critical: - **AEFI** = adverse event that occurs after vaccination but is not a reason to stop the series - **Contraindication** = condition making vaccination unsafe (e.g., anaphylaxis to vaccine component, encephalopathy within 7 days of dose) ### True Contraindications to DPT Vaccine 1. **Anaphylaxis** to any vaccine component (e.g., neomycin, streptomycin) 2. **Encephalopathy** within 7 days of previous DPT dose 3. **Uncontrolled seizures** or progressive neurological disease (relative contraindication; assess risk–benefit) 4. **Severe thrombocytopenia** (relative; assess bleeding risk) ### Clinical Pearl This infant had: - Low-grade fever (38.1°C) — well within expected range - Mild local swelling — typical post-injection reaction - **Complete resolution within 24 hours** — hallmark of benign AEFI These findings do NOT indicate contraindication. The vaccine series should continue. ### Management 1. **Administer DPT dose 2 as scheduled** 2. Counsel parents on expected mild reactions 3. Recommend paracetamol or ibuprofen **after** vaccination if fever develops (prophylactic use is not evidence-based) 4. Advise return if fever persists >48 hours or if severe reactions occur 5. Document the previous AEFI in the immunization record **Mnemonic:** **MILD AEFI = CONTINUE** — Mild fever, Irritability, Local swelling, Drowsiness → Continue vaccination series [cite:IAP Immunization Guidelines 2023, WHO Immunization Safety Surveillance 2022]