What is HIV?
HIV — human immunodeficiency virus — infects cells of the immune system, particularly CD4 T cells. Without treatment it gradually reduces the body's ability to fight infection. With treatment, people with HIV live long, healthy lives and can reach a viral load so low it cannot be transmitted to partners.
Diagnik Health Library · Updated
HIV and AIDS are not the same thing
HIV is the virus. AIDS is the most advanced stage of untreated HIV infection, defined by severe immune damage. Because effective treatment is widely available in the United States, most people diagnosed and treated today never progress to that stage.
How HIV is transmitted
- Anal or vaginal sex without a condom or without effective prevention.
- Sharing needles, syringes or other injection equipment.
- From parent to child during pregnancy, birth or breastfeeding — greatly reduced by treatment.
How HIV is not transmitted
- Hugging, kissing or shaking hands.
- Sharing food, cutlery, toilets or swimming pools.
- Insect bites.
Why testing is the only way to know
Early HIV can feel like a mild flu, or cause nothing at all, and the virus can be silent for years. The CDC recommends that everyone aged 13 to 64 is tested at least once, and more often for people with ongoing risk. An at-home oral-fluid test is one low-friction way to take that first step.
Tests mentioned in this guide
Frequently asked questions
- Is HIV curable?
- There is no cure, but HIV is treatable. Daily antiretroviral treatment can suppress the virus to undetectable levels, protecting health and preventing transmission to partners.
- Can I have HIV without symptoms?
- Yes. Many people have no symptoms for years. Testing is the only way to know your status.
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Find my testKeep reading
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HIV symptoms
Early HIV can feel like flu — or like nothing. Why symptoms are a poor guide, and what to do instead.
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How HIV testing works
Antibody, antigen/antibody and nucleic acid tests, and where an over-the-counter self-test fits.
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When should I take an HIV test?
Timing decides whether a result means anything. A practical guide to when to test.
Related testing pages
Sources
Educational information only, not a medical diagnosis or treatment advice. Screening results always need confirmation by a clinician.
This guide is general health information about screening tests. It is not a diagnosis and does not replace care from a clinician. See our medical disclaimer.