There are no set symptoms for HIV infection or AIDS. Most people who become infected with HIV do not notice they have been infected, although some may experience a flu-like illness shortly after infection.

People who have HIV may feel and look completely well, but they can pass the virus on despite this.

Once their immune system is compromised, people with HIV are more susceptible to opportunistic infections. Tumors or cancers that cause damage to the brain and nervous system can occur. These are the results of the opportunistic infections, however, and not of HIV infection itself.

For a diagnosis of AIDS, someone needs to have an opportunistic infection or tumor and a suppressed immune system.