Human immunodeficiency virus (HIV) is a chronic condition that affects the immune system’s ability to fight infections.
You can get HIV or pass HIV to someone through blood, semen and pre-seminal fluid, rectal fluid, vaginal fluid, and breast milk that contains the virus. The virus is transmitted from person to person when these body fluids come into contact with your body’s tissue, blood, or broken skin (e.g., open wounds).
The method of transmission for HIV can vary. You may get or pass HIV through:
Unprotected vaginal or anal sexSharing needles, syringes, and other drug injection equipmentPerinatal transmission from birth parent to child, such as through pregnancy, childbirth, or breastfeeding
When you get HIV, the virus attacks CD4 cells—a type of white blood cell that triggers the immune system to fight bacteria or viruses that make you sick. As your condition progresses, HIV can move through three stages: acute HIV, clinical latency, and AIDS. The symptoms of each stage can look different—those in an early stage of HIV can have flu-like symptoms, while those in an advanced stage can have severe infections.
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Stage 1: Acute HIV Symptoms
Acute (sudden) HIV starts two to four weeks after you get the virus. Acute HIV is also known as primary HIV.
During the acute stage, HIV multiplies very quickly in the immune system. Two-thirds of people in this stage experience flu-like symptoms, while some people don’t have symptoms at all.
Symptoms in the acute stage can last a few days to several weeks and may include:
ChillsFeverFatigueSwollen lymph nodesRashMouth ulcersNight sweatsMuscle achesSore throat
Symptoms can last a few days to several weeks. Acute stage HIV symptoms can mimic other conditions, like the flu or common cold—so, it’s important to not assume that you have HIV. If you think you may have been exposed to HIV, you may consider getting tested for the virus.
Stage 2: Clinical Latency Symptoms
The clinical latency stage—also called chronic HIV—is the second stage of HIV. In this stage, the virus continues to multiply but much more slowly than in the acute stage.
You might not experience any symptoms if you are in this stage of HIV. If you are not taking any treatment for HIV, you can still transmit the virus to someone else even if you have no symptoms. Without treatment, you can stay in the clinical latency stage for an average of 10–15 years. But symptoms and disease progression vary from person to person—and you can move through this stage more quickly or slowly than the average time.
However, if you are taking treatment, you can decrease your viral load (meaning the amount of HIV that you have that you can transmit to someone else) to an undetectable level. This stage can last for several decades while you're on treatment.
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Over time and without treatment, HIV can continue to slowly multiply and weaken your immune system. This can result in the third and final stage of HIV: acquired immunodeficiency syndrome (AIDS)—also known as late-stage HIV.
Symptoms of AIDS include:
Rapid weight loss (sometimes called wasting)Recurring feverFeeling extremely tiredDiarrhea that lasts for more than seven daysPneumoniaSores on the mouth, buttocks, and genitalsDepressionMemory lossColored blotches or patches on or under the skin and inside the mouth, nose, and eyelidsSwollen lymph nodes in the armpits, neck, and groin that last a long time
You may receive an AIDS stage diagnosis if:
The number of CD4 cells in your blood falls below 200 cells per cubic millimeter of blood (200 cells/mm3) You develop one or more opportunistic infections regardless of how many CD4 cells you have
In a healthy immune system, CD4 counts are between 500 and 1,600 cells per cubic millimeter of blood (cells/mm3)
AIDS symptoms are often related to opportunistic infections (OIs) or an AIDS-defining illness—which means that certain illnesses occur more frequently and severely in people with AIDS. OIs occur when HIV has caused too much damage to the body’s immune system and can no longer fight off infections.
The Centers for Disease Control and Prevention (CDC) outlines more than 20 OIs. Some of these infections include:
Invasive cervical cancerHerpes simplex virus (HSV)LymphomaTuberculosis (TB)PneumoniaSalmonellaKaposi’s sarcoma
Taking HIV medications as prescribed can slow disease progression and prevent AIDS. Without treatment, you can live with AIDS for about three years. If you develop an OI and are not taking treatment, your life expectancy can shorten to one year.
Deciding whether to take treatment or not isn’t always a choice. Not everyone has access to necessary healthcare services. This can be due to poverty, lack of insurance, racial disparities in the healthcare system, cultural stigma about HIV, and other factors.
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When to See a Healthcare Provider
The only way to know if you have HIV is to get tested. Knowing your HIV status is a powerful way to help take care of yourself and your partners.
Keep in mind: Don’t rely only on symptoms as a way to tell if you are living with HIV. HIV symptoms can mimic other conditions—and sometimes, you might not have any symptoms at all. If you think you may have been exposed to HIV, reach out to a healthcare provider or local clinic to learn more about testing.
You can get a test for HIV at your provider’s office, local health department, and family planning clinics, among others. You can also test for HIV at home. Testing is available for free if you have health insurance. If you do not have insurance, some testing sites still offer tests for free or on a sliding scale based on your income.
For more information about testing, please visit HIV.gov’s testing overview here.
To find an HIV testing site near you, please use the CDC resource here.
A Quick Review
HIV is a serious and chronic condition that attacks and destroys CD4 cells in your immune system. HIV can progress through three stages: the acute stage, the clinical latency stage, and the AIDS stage. Your symptoms may change depending on your HIV's current stage.
If you think you may have been exposed to HIV, it’s good practice to get tested because that is the only way you can confirm a diagnosis and rule out other conditions.