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HIV is a virus called Human Immunodeficiency Virus which causes HIV infection. Once the virus enters the body, it attacks the CD4 cells in the immune system, and leaves its genetical materials in the cell. It uses the DNA of CD4 cell for self-reproduction and mixes back with blood in larger amounts by destroying the cell. It gradually causes the cells of the immune system to decrease, and destroys the defense system against other bacterial or viral diseases.

AIDS, Acquired Immune Deficiency Syndrome, is the advanced stage of HIV infection. It decreases the number of the main cells in the immune system, CD4 cells, by infecting them. If the disease is not treated after the virus is transmitted, the immune system’s defense starts to fail within 10-12 years. When defense is insufficient, the body becomes vulnerable to all infections, and sometimes more than one infection occur. AIDS is the stage when the immune system fails to function due to HIV and other infections called opportunistic infections occur, sometimes alone and sometimes together. AIDS is not a disease in its own right.

Often-used definitions such as AIDS disease, AIDS patient or person with AIDS are wrong. People who are diagnosed during the time when cells of immune system decrease and diseases called opportunistic infections occur (such as plague, pneumonia, meningitis, CMV infection, toxoplasmosis etc.) are the ones diagnosed with HIV infection at AIDS stage. Anyone living with HIV is not at AIDS stage, and people taking treatment never get to AIDS stage throughout their lives.

People diagnosed with HIV infection at AIDS stage can be cured and escape this stage.

HIV Infection is the clinical process that starts upon encountering HIV. HIV infection is a treatable chronic infection. With the effective treatments started in 90s, HIV infection was removed from World Health Organization’s fatal diseases list, and is now among chronic diseases such as hypertension and diabetes which can be manageable throughout one’s life.

Today, people living with HIV can have a standard lifespan without having any HIV-borne health issues.

Stages of the Infection


It’s the stage upon encountering HIV infection and getting infected by HIV. It’s explained further in the section “Ways of Transmission, How Is It Transmitted? Risky Behaviors”.

2-First Stage of HIV Infection (Acute HIV Infection)

First symptoms may occur within 2-4 weeks after being infected with HIV. Most people infected with HIV show no symptoms at all. Most patients do not recall going through this stage. Clinical findings during this stage are not HIV-specific and are variable. The most common symptoms are high fever, swollen lymph glands, sore throat, rash, muscle and joint pains, and sometimes diarrhea, headache and vomiting. All these symptoms are organically healed within 2-3 weeks. From this stage on, the person is infective, and it’s the stage when transmission is at its peak.

During this stage, Anti-HIV antibody testing in the blood is usually negative (it’s called the window period). And laboratory tests show that P24 and viral load are positive.

3 Seroconversion Stage

It’s the stage when HIV infection starts to appear in laboratory tests. Further information on this stage, diagnosis tests, window periods, false positivity and negativity is available in the relevant section.

4 Asymptomatic Stage

It’s the stage when initial HIV infection ends. At this stage, people living with HIV show no symptoms at all. They maintain their standard health condition and go on with their lives. At this stage, which can last about 10-12 years, HIV continues to replicate itself and decrease the number of CD4 cells by using CD4 cells.

The transmission started with initial HIV infection continues at this stage, too. HIV can be diagnosed via voluntarily performed check-ups, or via laboratory tests taken prior to procedures such as surgery, marriage arrangements, before starting a job, or blood donation and so on. Infection that’s been diagnosed by tests is subjected to an immediate treatment by following UN and WHO’s recommendations. Clinical charts of the person taking treatment don’t move on further than asymptomatic stage, amount of virus in their blood is reduced to an undetectable level, and they maintain a healthy life.

5 Early Symptomatic Stage

It’s the stage when person starts to show symptoms due to weakening of the immune system during the asymptomatic stage, and feels compelled to consult a doctor. People not taking treatment, or discontinued the treatment, or resistant to the treatment may show HIV-specific symptoms after the asymptomatic stage. Fatigue, headache, losing more than 10% of total body weight (which should not be confused with weight loss due to nutritional deficiency caused by excessive stress and anxiety during the post-diagnosis trauma period and the time period between first suspicion of HIV and final diagnosis), idiopathic fever, incurable diarrhea that lasts more than one month, a disease called seborrheic dermatitis which causes skin to develop scaly patches that flake off, common and often herpes virus infections (facial and genital herpes), fungal infections in mouth (monilia) are the most common symptoms. As in asymptomatic stage, infection appears in the laboratory tests at this stage, too. A treatment plan is developed by performing CD4 cell count (immune system) and viral load count (amount of virus in 1ml of blood).

6 Acquired Immune Deficiency Syndrome / Late Symptomatic Stage

It’s the stage when some microorganisms that don’t cause disease (bacterias, viruses, fungi, parasites) start to cause disease in HIV negative people or people living with HIV taking treatment, due to not being diagnosed, not taking or discontinuing the treatment at third, fourth and fifth stages of the infection. Symptoms of immune system deficiency start to appear. And at this stage, specific cancer types called opportunistic cancers (Kaposi sarcoma, brain lymphoma etc.) may develop. Those who are diagnosed at this stage are immediately admitted to treatment. People who are diagnosed at Acquired Immune Deficiency Syndrome stage (AIDS stage) can restore their health with today’s effective treatments and go back to asymptomatic stage.

AIDS (Acquired Immune Deficiency Syndrome) is not a disease in its own right. It’s the sixth stage of HIV infection.

7 Advanced Stage

People not taking treatment despite being diagnosed at AIDS stage, or not yet diagnosed ones show symptoms of myolysis and significant nervous system involvements at this stage due to infection. Not being treated until this stage usually results in death.