The first symptoms of HIV infection can resemble symptoms of common cold or flu viruses. The symptoms of early infection can also be similar to the symptoms of other sexually transmitted diseases and other infections such as "mono" or hepatitis, which are much more commonly and more easily transmitted. Stress and anxiety can also produce symptoms in some people, even though they do not have HIV.

Some people who contract HIV experience very strong symptoms, but others experience none at all. Those who do have symptoms generally experience fever, fatigue, and, often, rash. Other common symptoms can include headache, swollen lymph nodes, and sore throat. These symptoms can occur within days or weeks of the initial exposure to the virus during a period called primary or acute HIV infection.

Because of the nonspecific symptoms associated with primary or acute HIV infection, symptoms are not a reliable way to diagnose HIV infection. Testing for HIV antibodies is the only way to know whether you have been infected; however, the HIV antibody test only works after the infected person's immune system develops antibodies to HIV. During the "window period" between the initial infection and the period in which antibodies are detectable (which can be from 2 weeks to 6 months, but is usually 3 months), standard HIV testing is ineffective.

If you are concerned that you may have recently acquired HIV and have symptoms described above, see a doctor. A doctor or other health care professional can help determine whether you may be infected with HIV or another infection. If HIV infection is suspected, he or she may perform a Polymerase Chain Reaction (commonly called "PCR") test to determine whether HIV is present in the blood.

Once the primary or acute infection is over, most people do not experience any visible symptoms for another 8-10 years. Left untreated, the immune system becomes increasingly weaker and the disease progresses to AIDS. The next symptoms experienced by individuals infected with the virus are often associated with the "opportunistic infections" that target individuals with AIDS such as pneumonia, tuberculosis, and toxoplasmosis.