What Is HIV? HIV vs AIDS Explained
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
HIV is a virus that attacks the immune system, and without treatment it can progress to AIDS over roughly 8 to 10 years. Modern antiretroviral therapy keeps the virus suppressed, so most people with HIV live long, healthy lives. HIV and AIDS are not the same thing: AIDS is the late stage of an untreated HIV infection.
What does HIV stand for and what does it do?
HIV stands for human immunodeficiency virus. It attacks CD4 cells, which are the immune system's command centers, and over time it can weaken the body's ability to fight off infections. The virus spreads through blood, semen, pre-seminal fluid, rectal fluid, vaginal fluid, and breast milk. It does not spread through saliva, air, toilet seats, or hugging. With treatment, the virus is kept at very low levels, and the immune system stays strong enough to protect you.
What is the difference between HIV and AIDS?
HIV is the virus itself. AIDS, which stands for acquired immunodeficiency syndrome, is the late stage of an untreated HIV infection. Without treatment, HIV typically progresses to AIDS over roughly 8 to 10 years, when CD4 cells drop below 200. Not everyone with HIV develops AIDS, and with antiretroviral therapy most people never reach that stage. The two terms are often used interchangeably, but they describe different points on the same timeline.
What does AIDS stand for?
AIDS stands for acquired immunodeficiency syndrome. It is the most advanced stage of HIV infection, defined by a severely damaged immune system, specifically a CD4 count below 200. At this stage the body becomes vulnerable to opportunistic infections. The key point is that AIDS is preventable: consistent antiretroviral therapy keeps the virus suppressed and stops the progression from HIV to AIDS in nearly everyone who stays on treatment.
Can you live a normal life with HIV?
Yes. Antiretroviral therapy, or ART, makes HIV a manageable condition rather than a fatal one. When treatment keeps the viral load below 200 copies per milliliter, the virus is undetectable, and undetectable means untransmittable, a concept known as U=U. People on effective ART can expect near-normal lifespans, and they cannot pass the virus to sexual partners. The earlier HIV is found, the better the long-term outlook.
How is HIV diagnosed?
HIV is diagnosed with a blood test. A 4th-generation antigen-antibody test is reliable 18 to 45 days after exposure, often within 2 to 6 weeks. An HIV RNA test can detect the virus earlier, around 10 to 14 days after exposure. Because symptoms are often absent or flu-like, testing is the only reliable way to know your status. The CDC recommends that every adult aged 13 to 64 get tested for HIV at least once.
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Frequently asked questions
Can HIV be cured?
There is no cure for HIV yet, but antiretroviral therapy keeps the virus suppressed so most people live long, healthy lives.
Is HIV the same as AIDS?
No. HIV is the virus, and AIDS is the late stage of an untreated HIV infection that usually develops after 8 to 10 years without treatment.