HIV/AIDS

HIV infection is a chronic viral disease whose advanced stage is called acquired immunodeficiency syndrome, or AIDS. HIV inserts its genetic material into host cells and progressively disrupts immune function, particularly through depletion or impairment of CD4 T cells. AIDS is diagnosed when HIV has caused severe immune damage, commonly defined by a very low CD4 count or the presence of specific opportunistic infections or cancers.¹

The course varies substantially. Some people experience a short, flu-like illness soon after infection; others have no noticeable symptoms for years. Untreated infection can eventually produce weight loss, persistent fever, tuberculosis, fungal disease, bacterial infections, or malignancies such as Kaposi sarcoma and certain lymphomas. Antiretroviral therapy can suppress HIV replication, restore immune function, and prevent progression to AIDS.

HIV is transmitted when infected blood, semen, vaginal fluids, or breast milk enters another person’s body through specific exposure routes. Sexual transmission and sharing contaminated injection equipment are major routes; transmission can also occur during pregnancy, childbirth, or breastfeeding. HIV is not spread by casual contact, hugging, sharing dishes, insect bites, or ordinary household interaction.¹

Prevention combines several measures. Condoms, sterile injecting equipment, regular testing, treatment of sexually transmitted infections, and antiretroviral medicines used as pre-exposure prophylaxis or post-exposure prophylaxis all reduce risk. Treatment during pregnancy and appropriate infant-feeding strategies have greatly reduced, though not eliminated, perinatal transmission. A person taking therapy who maintains an undetectable viral load has no risk of sexually transmitting HIV, summarized by the public-health phrase “undetectable equals untransmittable,” or U=U.²

HIV testing is the only reliable way to determine infection, because symptoms may be absent and tests have a window period after exposure. Laboratory antigen-and-antibody tests, antibody tests, and nucleic-acid tests differ in how soon they can detect infection. A positive screening result requires confirmatory testing, while recent exposure may call for repeat testing or an HIV RNA test.³

Antiretroviral therapy uses combinations of medicines that block different stages of the viral life cycle. Modern regimens are usually once daily, highly effective, and recommended for everyone with HIV as soon as possible after diagnosis. Therapy does not eradicate latent virus from the body, so treatment is generally lifelong. Adherence, drug-interaction review, monitoring of viral load and CD4 count, and attention to cardiovascular, kidney, liver, bone, and mental health are part of continuing care.⁴

HIV/AIDS is both a medical condition and a public-health challenge shaped by inequality, stigma, and access to care. The burden is unevenly distributed across regions and populations, with major effects in sub-Saharan Africa and among communities facing poverty, discrimination, criminalization, unstable housing, or limited health services.⁵

Effective responses combine biomedical tools with confidential testing, community-based services, harm reduction, sexual-health education, and protection from discrimination. Earlier diagnosis and sustained treatment benefit individuals while reducing community transmission. The history of HIV care also demonstrates the importance of patient activism: advocacy helped accelerate clinical research, expand access to experimental medicines, and make affected communities participants in research and policy rather than merely recipients of care.

HIV is not a single uniform virus: HIV-1 causes most global infections, while HIV-2 is less transmissible and concentrated mainly in West Africa, although cases occur elsewhere. HIV also has substantial genetic diversity, which complicates vaccine development and can influence drug resistance and diagnostic design.¹

Some people control HIV without sustained treatment, including rare “elite controllers” who maintain very low viral levels; they are scientifically important but uncommon and should not be treated as a model for usual care. Another overlooked point is that viral suppression protects both health and sexual partners, whereas an undetectable result is not permanent: missed doses, treatment interruption, or drug resistance can allow viral load to rebound. Researchers continue to study long-acting medicines, broadly neutralizing antibodies, vaccines, and strategies aimed at eliminating or permanently silencing latent virus.

HIV

Human immunodeficiency virus, the virus that can progressively damage the immune system.

AIDS

Acquired immunodeficiency syndrome, the advanced stage of HIV infection defined by severe immune suppression or certain opportunistic illnesses.

CD4 T cell

An immune cell targeted and depleted by HIV; its count helps assess immune function.

Viral load

The amount of HIV in a person’s blood, used to monitor treatment and transmission risk.

Antiretroviral therapy

Combination treatment that suppresses HIV replication.

PrEP

Pre-exposure prophylaxis: antiretroviral medicine taken by people without HIV to prevent infection.