What is the difference?

HIV vs AIDS

HIV and AIDS are often said in one breath, which leads many people to think they are the same thing. HIV is the virus; AIDS is the most advanced stage of illness that can develop if HIV goes untreated.

General information, not medical advice. For advice about your own situation, talk to a clinician, pharmacist or sexual health clinic.

STIs

HIV

HIV is a virus that weakens the immune system by attacking CD4 cells; with modern treatment, people living with HIV can expect a near-normal lifespan.

Full entry
STIs

AIDS

AIDS is the most advanced stage of untreated HIV infection, when the immune system is badly damaged and serious infections or cancers can develop.

Full entry

Side by side

HIVAIDS
What it isHIVA virus that attacks CD4 cells in the immune system.AIDSA late stage of untreated HIV infection, not a separate virus.
Can you catch it?HIVYes, through certain body fluids, for example during sex without a condom or PrEP.AIDSNo, it is not caught directly; it develops from untreated HIV, usually over many years.
How it is identifiedHIVA blood test, including rapid tests and self-tests.AIDSA very low CD4 count or the appearance of certain opportunistic illnesses.
Effect of treatmentHIVAntiretroviral therapy controls the virus and allows a near-normal lifespan.AIDSTreatment usually prevents it, and can help the immune system recover even after a diagnosis.
Other namesHIVHuman immunodeficiency virus.AIDSMany health bodies now prefer "advanced HIV disease".

In short

Everyone with AIDS has HIV, but most people with HIV today will never develop AIDS, thanks to treatment.

What they have in common

Both are part of the same condition, and both are addressed by HIV testing and effective antiretroviral treatment.

Sources

  1. WHOHIV and AIDS fact sheet
  2. HIV.govWhat are HIV and AIDS?
  3. NHSHIV and AIDS

More comparisons

Last reviewed 10 October 2026. Spotted a mistake?