HIV is transmitted primarily through direct contact with certain body fluids from a person who has HIV and a detectable viral load. These fluids include blood, semen (cum) and pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk. Transmission occurs when these fluids come into contact with a mucous membrane (such as inside the rectum, vagina, penis, or mouth), damaged tissue, or are directly injected into the bloodstream via needles or syringes. The main ways HIV is transmitted are:
- Having anal or vaginal sex with someone who has HIV without using protection like condoms or preventive medicines.
- Sharing needles, syringes, or other drug injection equipment contaminated with HIV.
- From mother to child during pregnancy, childbirth, or breastfeeding (called perinatal transmission).
- Less commonly, through blood transfusions or organ/tissue transplants with infected blood, though this risk is extremely low in settings with proper screening.
- Rare cases of transmission can occur through needlestick injuries in healthcare settings.
HIV is not transmitted through casual contact such as touching, hugging, shaking hands, sharing toilets, food, drinks, or everyday household items. Oral sex carries little to no risk, and HIV does not spread through saliva, sweat, tears, or kissing without blood contact. Effective HIV treatment that achieves an undetectable viral load prevents transmission through sex. In summary, HIV transmission requires the exchange of specific body fluids into the bloodstream or mucous membranes, mainly through unprotected sex, sharing needles, and from mother to child during birth or breastfeeding.
