A 6-month-old infant born to an HIV-positive mother on antiretroviral therapy (CD4 count 450/μL) presents to the immunisation clinic. The mother asks about the safety and timing of the next dose of polio vaccine. The child has received BCG, Hepatitis B birth dose, and first dose of pentavalent vaccine on schedule. What is the most appropriate next step in management?

Explanation

## Management of Immunisation in HIV-Exposed Infants ### Clinical Context This is an HIV-exposed infant (mother on ART with CD4 >200/μL), not yet confirmed HIV-positive. The key decision is vaccine selection based on maternal immune status and infant HIV status. ### Key Point: **In HIV-exposed infants born to mothers with CD4 >200/μL on ART:** - IPV (inactivated polio vaccine) is preferred over OPV - OPV is contraindicated in confirmed HIV-positive children with CD4 <200/μL (risk of vaccine-derived poliovirus) - Live vaccines (rotavirus, MMR, varicella) are deferred until immune reconstitution ### High-Yield: **National Immunisation Schedule (NIS) modification for HIV-exposed children:** - Pentavalent, IPV, hepatitis B, DPT, meningococcal conjugate → given as per schedule - OPV → replaced with IPV - Live vaccines (rotavirus, MMR, varicella) → deferred until CD4 >200/μL (if HIV-positive) - BCG → given at birth (before HIV status known) ### Decision Algorithm ```mermaid flowchart TD A[HIV-exposed infant]:::outcome --> B{Mother on ART?}:::decision B -->|Yes, CD4 > 200| C[Infant likely uninfected]:::outcome B -->|No or CD4 < 200| D[High transmission risk]:::urgent C --> E{Next vaccine?}:::decision E -->|Polio dose| F[Give IPV, NOT OPV]:::action E -->|Live vaccine| G[Defer until CD4 > 200 if HIV+]:::action D --> H[Confirm infant HIV status first]:::action ``` ### Clinical Pearl: **OPV shedding risk:** In immunocompromised children, OPV can replicate and cause vaccine-derived poliovirus (VDPV). India's transition to IPV-dominant schedule (2015 onwards) prioritizes this safety concern. ### Reasoning: The correct approach is to continue scheduled immunisation with **IPV instead of OPV**, and defer live vaccines. The mother's CD4 >200/μL suggests low transmission risk, so routine immunisation (non-live) proceeds without delay. Infant CD4 testing is not routine for exposed infants; it is done only if HIV infection is suspected clinically or serologically.