A 6-week-old infant born to a mother with active tuberculosis (on anti-TB therapy for 2 weeks) presents for routine immunisation. According to IAP guidelines, which vaccine should be deferred and which should be given?

## BCG and Live Vaccine Deferral in Infants Exposed to Active Tuberculosis **Key Point:** Infants born to mothers with active tuberculosis (even if on anti-TB therapy) should NOT receive BCG until tuberculin skin test (TST) or IGRA is negative, to avoid BCG disease in a potentially infected infant. Inactivated vaccines can be given safely. ### Risk Assessment in Maternal TB | Scenario | BCG Status | Other Vaccines | Rationale | | --- | --- | --- | --- | | Mother with active TB (on therapy <2 weeks) | **DEFER** | Give inactivated | Risk of infant TB infection; BCG contraindicated if infected | | Mother with active TB (on therapy >2 weeks, non-infectious) | **DEFER until TST/IGRA negative** | Give inactivated | Infant may be infected but asymptomatic; TST/IGRA needed first | | Mother with latent TB (TST+, no disease) | **Give BCG** | Give all vaccines | No active disease; infant not at risk of infection | | Mother with TB on therapy, infant TST/IGRA negative | **Give BCG** | Give all vaccines | Infant confirmed uninfected | ### Why BCG is Deferred 1. **BCG is a live vaccine** — contraindicated in TB-infected individuals 2. **Risk of BCG disease** — if the infant is already infected with *Mycobacterium tuberculosis*, BCG can cause disseminated BCG infection (BCG-itis, BCG osteomyelitis) 3. **TST/IGRA must be done first** — to confirm the infant is not infected before giving BCG **High-Yield:** Even if the mother is on anti-TB therapy for 2 weeks, the infant may still be infected (incubation period can be weeks to months). TST/IGRA at 6 weeks may be falsely negative due to early infection; repeat at 3 months if initial test is negative. ### What CAN Be Given at 6 Weeks? **Inactivated vaccines are safe:** - DPT (diphtheria, pertussis, tetanus) - IPV (inactivated polio vaccine) - Hepatitis B vaccine - PCV (pneumococcal conjugate vaccine) - Rotavirus vaccine (if available) **Live vaccines to defer:** - BCG - Rotavirus (if live formulation used) - MMR (later, at 9–12 months) ### Timeline for BCG After Maternal TB ```mermaid flowchart TD A[Infant born to mother with active TB]:::outcome --> B[Perform TST/IGRA at 6 weeks]:::action B --> C{TST/IGRA negative?}:::decision C -->|Yes| D[Repeat TST/IGRA at 3 months]:::action C -->|No| E[Infant has TB infection]:::urgent D --> F{Still negative?}:::decision F -->|Yes| G[Give BCG at 3 months]:::action F -->|No| H[Refer for TB prophylaxis]:::urgent E --> H ``` **Clinical Pearl:** Isoniazid prophylaxis may be considered for the exposed infant while awaiting TST/IGRA results, depending on the duration of maternal infectivity and local TB epidemiology. [cite:IAP Immunisation Guidelines 2023, WHO TB and Immunisation Guidelines]