Understanding HIV Transmission: How AIDS Is Acquired

Transmission Routes

1. Sexual Contact: Unprotected vaginal, anal, or oral sex with an HIV+ partner. Receptive anal highest risk. Viral load = transmissibility (U=U: undetectable = untransmittable).
2. Blood Exposure: Sharing needles/syringes (PWID), needlestick injuries (healthcare), unsafe medical injections, unscreened blood transfusions (rare in high-income countries).
3. Perinatal (Mother-to-Child): During pregnancy, delivery, or breastfeeding. Without intervention: 15–45% transmission. With ART + C-section + formula feeding: <1%.

NOT Transmitted By

• Casual contact (hugging, shaking hands, sharing utensils, toilets).
• Air, saliva, sweat, tears, urine, feces (unless blood-contaminated).
• Insects (mosquitoes).

Prevention

• Condoms, PrEP (pre-exposure prophylaxis), PEP (post-exposure), TasP (treatment as prevention), sterile needles, screened blood, prenatal ART.