HIV exposure and infection in children — formative SAQs

SAQ 1 (10 marks)

A term infant is born to a 26-year-old mother whose HIV is well controlled on combination antiretroviral therapy, with an undetectable viral load at delivery. The mother intends to formula-feed. Outline the management of this HIV-exposed infant from birth until infection is confidently excluded. ^[7]

Question: Describe the stepwise management of this HIV-exposed infant, including infant prophylaxis, cotrimoxazole, diagnostic testing and follow-up. (10 marks) ^[7]

Model answer

Infant antiretroviral prophylaxis (2 marks). Because the mother is suppressed and the infant is low-risk, give nevirapine prophylaxis, typically for four to six weeks. State that a higher-risk infant — for example one born to a viraemic or newly diagnosed mother — would also receive zidovudine, and that the prophylaxis duration and regimen are matched to the transmission risk. ^[7]

Cotrimoxazole prophylaxis (2 marks). Start cotrimoxazole at four to six weeks of age and continue it until infection has been excluded, because Pneumocystis pneumonia is a leading cause of infant HIV mortality and prophylaxis is effective and cheap. State the principle: prophylaxis covers the window between exposure and a confident exclusion of infection. ^[8]

Diagnostic testing — PCR, not antibody (3 marks). The diagnosis of infant HIV uses HIV DNA or RNA PCR, because maternal IgG crosses the placenta and persists for up to 18 months, making antibody testing uninterpretable in the infant. Perform a PCR at four to six weeks; because this infant is low-risk and replacement-fed, a birth PCR is not strictly required but is often included. A negative result early does not exclude late infection, so confirm with a final HIV antibody test at 18 to 24 months, when maternal antibody has cleared. A single positive PCR must be confirmed with a second sample before labelling the child infected. ^[7]

Feeding, follow-up and the family layer (3 marks). Because the mother is formula-feeding, support safe replacement feeding and confirm access to clean water and reliable supply. Ensure the mother remains on lifelong ART (Option B+) with continued viral suppression, offer partner and sibling testing, and reinforce that the suppressed maternal viral load is the single strongest predictor of no transmission. Arrange structured follow-up through the specialist paediatric HIV service until the final antibody test is negative and the chapter is closed. ^{[3] [7]}