Vertical transmission of HIV occurs primarily through which routes?

• A. Transmitted by sexual contact and exposure to contaminated blood
• B. Transmitted only through breast milk
• C. Transmitted exclusively through casual contact
• D. Transmitted only via respiratory droplets

Answer: (A)

Vertical transmission means the baby acquiring HIV from the mother during pregnancy, delivery, or breastfeeding. The most relevant route in the perinatal period is exposure to maternal blood and secretions during birth, which is captured by the element of exposure to contaminated blood in the option. This reflects the peripartum transmission risk when the infant is exposed to maternal blood and fluids as the baby passes through the birth canal. Although breastfeeding is also a route of vertical transmission, none of the choices fully states all modes; the other options mischaracterize transmission—breast milk alone is not the only route, casual contact does not transmit HIV, and respiratory droplets are not a mode of HIV transmission. Therefore, the option highlighting exposure to contaminated blood aligns best with how vertical transmission can occur during delivery.