What is HIV?
HIV stands for Human Immunodeficiency Virus. HIV is the virus that causes AIDS.
Your immune system is your body’s defense system. While many viruses can be controlled by the immune system, HIV targets and infects the same immune system cells that are supposed to protect us from illnesses. These are a type of white blood cell called CD4 Cells (sometimes called T-cells).
HIV takes over CD4 cells and turns them into factories that produce thousands of copies of the virus. As the virus makes copies, it damages or kills the CD4 cells, weakening the immune system.
What is AIDS?
AIDS stands for Acquired Immune Deficiency Syndrome. AIDS is the most advanced stage of HIV infection.
HIV causes AIDS by attacking CD4 cells, which the immune system uses to protect the body from disease. When the immune system loses too many CD4 cells, you are less able to fight off infection and can develop serious, often deadly, infections. These are called opportunistic infections (OIs).
When someone dies of AIDS, it is usually OIs or other long-term effects of HIV that cause death. AIDS refers to the weakened state of the body’s immune system that can no longer stop OIs from developing and becoming so deadly.
What is the Difference Between HIV and AIDS?
You don’t have AIDS as soon as you are infected with HIV. You can be HIV+ for many years with no signs of disease, or only mild-to-moderate symptoms. But without treatment, HIV will eventually wear down the immune system in most people to the point that they have low numbers of CD4 cells and develop more serious OIs.
The Centers for Disease Control and Prevention (CDC) identifies someone as having AIDS if he or she is HIV+ and has one or both of these conditions:
- At least one AIDS-defining opportunistic infection (see list of OIs in our info sheet called AIDS Defining Conditions)
- A CD4 cell count of 200 cells or less (a normal CD4 count is about 600 to 1,500)
HIV cannot be transmitted except when certain body fluids are exchanged. You can greatly reduce the risk of transmission by:
- Avoiding contact with sexual fluids by always practicing safer sex
- Abstaining from sex unless you and your partner are both HIV-negative and in a long-term, monogamous relationship
- Not injecting drugs, or if you do, always using new or clean needles
- Finding out your HIV status if you are planning to get pregnant and working with a knowledgeable health care provider and obstetrician if you are HIV+
If you protect yourself in these ways, you do not need to be afraid of getting or passing HIV by casual contact. Remember, HIV is not transmitted by:
- Sharing food or drinks
- Using a shower, bath, or bed used by an HIV+ person
- Kissing (between people with no significant dental problems)
- Sharing exercise equipment
- Bug bites