Undetectable HIV treatment blocks sexual transmission
HIV is a preventable retrovirus that can progress to AIDS without care, yet modern therapy can make it a long-term manageable condition. Someone kept at an undetectable viral load through sustained treatment has effectively no risk of passing the virus sexually.
Untreated infection moves through three stages. Two to four weeks after exposure, between 40 and 90 percent of people develop a flu-like or glandular-fever-like illness with fever, swollen nodes, sore throat and often a rash, which doctors easily mistake for something common. A long quiet phase follows, lasting anywhere from about three to more than twenty years and averaging roughly eight. AIDS is diagnosed when CD4 helper cells fall below 200 per microlitre of blood or when telltale illnesses appear, most often pneumocystis pneumonia.
Without treatment, about half of infected people reach AIDS within ten years and average survival is around eleven. A few buck the pattern: roughly 5 percent keep healthy CD4 counts for over five years without drugs, and about one in 300, the elite controllers, hold the virus at low or undetectable levels on their own. For everyone else, lifelong antiretroviral therapy started early can restore near-normal life expectancy, so people die with the virus rather than of it.
Transmission runs mainly through unprotected sex, shared needles or contaminated transfusions, and from mother to child in pregnancy, birth or breastfeeding; saliva, sweat and tears do not carry it, and oral sex carries little risk. Prevention now includes condoms, pre-exposure and post-exposure drugs, needle exchanges, and antiretrovirals for mother and baby.
HIV crossed into humans from other primates in west-central Africa in the early to mid twentieth century, and the US CDC first recognised AIDS in 1981. By 2024 it had killed at least 42.3 million people, and in 2025 some 40.9 million were living with the virus, with 1.2 million new infections that year. The epidemic has also bred stigma, myths about casual contact and religious disputes over condoms; the NIH and Gates Foundation have pledged $200 million toward a cure.
Source: HIV/AIDS
