A variety of HIV risk factors can increase your chances of becoming infected with a virus called HIV (human immunodeficiency virus). This infection can lead to AIDS (acquired immunodeficiency syndrome), which makes it more difficult for your body to fight off infection and disease. Some risk factors increase your HIV risk more than others. You can't entirely eliminate risk, but you can do many things to lower your risk and protect yourself.
“Immunodeficiency” means the systems that fight illnesses in your body either aren’t working or aren’t there.
Your immune system has cells called CD4 or T cells that help keep you healthy. HIV attacks these cells. The virus copies itself over and over, and the number of CD4 cells in your body goes down. This makes it hard for your body to protect itself from germs.
AIDS stands for “acquired immunodeficiency syndrome.” HIV can become this disease if it’s not treated.
More than 1.2 million people in the U.S. have an HIV infection. Nearly 27,000 have AIDS. It's the third, and most advanced stage of the infection.
When you have HIV, your doctor will watch the amount of the virus in your system. You may hear this amount called your “viral load.” Two things will tell your doctor if it has become AIDS:
Your CD4 count. A healthy immune system has a CD4 count of 500 to 1,600. A person with AIDS has a CD4 count below 200.
AIDS-defining infections. These can worsen your HIV. They’re called also called opportunistic infections. Viruses or bacteria that don’t usually make healthy people sick can cause them in someone with HIV.