HIV → AIDS Progression
HIV Transmission — What Transmits / What Does NOT
| Transmits HIV | Does NOT Transmit HIV |
|---|---|
| Sexual intercourse (unprotected) | Casual contact (handshakes, hugs) |
| Blood transfusion with infected blood | Mosquito or insect bites |
| Sharing contaminated needles/syringes | Sharing utensils or food |
| Mother → child (transplacental, intrapartum, breastfeeding) | Saliva, tears, sweat (extremely low viral load) |
| Organ transplant from infected donor | Toilet seats, swimming pools |
Why ELISA Can Be False Positive in Neonates
- Maternal IgG (including anti-HIV IgG) crosses the placenta
- ELISA detects IgG antibodies — detects maternal antibodies in neonate's blood for up to 18 months
- Use PCR (viral RNA) or proviral DNA detection to diagnose HIV in children under 18 months
Clinical Application of Immunology Knowledge
- Vaccine schedules: BCG at birth → active artificial immunity against TB
- Post-exposure prophylaxis (PEP): antiretrovirals within 72h of HIV exposure
- Passive immunization: anti-rabies immunoglobulin (RIG) + vaccine for rabies exposure
- Prenatal screening: ELISA for HIV, syphilis, hepatitis B to prevent vertical transmission