What are HIV and AIDS?

Most people with HIV don't know exactly when they got it, or how long they had it before they were tested. A person can learn that they have HIV at any stage of the disease.

In the United States and other developed countries, the average time from getting infected with HIV to advanced AIDS is about 10 years if the person gets no treatment. About 1 in 5 of these people will develop AIDS within 5 years or less. Only about 1 in 20 of the people infected with HIV will still have normal T helper cell counts for 10 to 15 years without treatment. But with treatment, most people can postpone AIDS.

Over time, HIV usually goes from infection to AIDS in 4 stages:

• Acute or primary infection – some people get sick with flu-like symptoms
• Asymptomatic phase – no signs of disease, but HIV test is positive
• Early symptomatic phase – some health problems, mostly mild; HIV test is still positive
• Advanced HIV or AIDS – serious infections and cancer; HIV test is still positive

Below are general descriptions of these stages of HIV infection. Each person is different, and his or her progression through infection, symptoms, response to treatment, and many other factors all affect the course of illness.

Primary infection

The first or acute infection stage is known as the primary infection, acute HIV infection, or seroconversion syndrome. This starts when HIV enters the body and starts growing (making more viruses) in cells. This stage usually starts soon after infection, and lasts from 2 to 6 weeks. During this time, T helper cell counts in the blood drop. Later, the T helper cell count may go back up to normal or near normal, even with no treatment.

Different people have different symptoms during this stage. Some will notice no symptoms. Many people have fever, headache, flu-like symptoms, extreme tiredness, swollen lymph nodes, sore throat, rash, nausea, vomiting, diarrhea, or muscle and joint aches. The person may decide not see a doctor for mild symptoms. Others will see the doctor if symptoms are severe or last a long time. But even a doctor may not suspect HIV unless the person mentions a recent HIV exposure such as unprotected sex or shared needle use.

HIV antibody tests are usually negative during this phase. If HIV is suspected, other tests can be done to find out if it is present. But during this time, there are very high viral counts in the blood, and the person is very contagious. That means he or she can more easily pass the virus on to others through unprotected sex or sharing injection equipment than in the next stage of infection.

By the end of this stage, the symptoms are mostly gone, but HIV is inside the lymph nodes, spleen, and other organs and tissues of the body. For most people, there is less virus in the blood as this stage ends than during the first few weeks. In some people, the viral load stays high, and HIV infection can get worse quickly through the next stage.

The asymptomatic stage

The asymptomatic (no symptoms) stage is usually the longest stage. It can last for as little as one year or more than 15 years. During this time the person has few or no symptoms that would be recognized as HIV. The virus is still multiplying and damaging immune cells, even though the T helper cell count may be normal (above 500) or slightly low (350-499). Most often, the T cell count slips lower and lower over time unless anti-HIV treatment is started.

Sometimes people get certain infections during this stage. Some of these are infections by germs that rarely cause disease in healthy people but are quite common in people with HIV. Everyday infections such as warts and sinus infections may also happen more often. But overall, most people have very few symptoms that are clearly related to HIV at this time. Even so, they can pass the virus on to others during unprotected sex, by sharing needles, or during pregnancy.

People who are found to have HIV during this stage should first have a complete medical review and a thorough physical exam by a clinician who is an expert in HIV. This may be a doctor, nurse practitioner, or physician assistant who sees many HIV-infected patients and keeps up with the newest treatments. Patients should have regular visits with the clinician whether or not they are taking HIV treatment. These visits usually include a brief physical exam and tests for viral load and CD4 counts (T cells). If the T helper cell count is low or the viral load is high, anti-HIV drugs may be started during this stage. Some doctors will prescribe anti-HIV drugs no matter what these tests show, if the patient is ready to take them.

By the end of this stage, the number of helper cells in the blood is usually quite low. Other parts of the immune system may also be damaged, lowering a person's ability to fight off infections and certain other diseases even further.

Early HIV symptoms

Early symptoms can start as T helper cell counts drop. Often there will be one or more infections that are not serious enough to qualify as AIDS. They may go along with a rise in the viral load in the blood.

Infections seen at this stage may include fungal infections (such as thrush in the mouth or vaginal yeast infections), herpes simplex (genital or mouth sores), shingles (a painful outbreak of chickenpox-like sores), bronchitis (infection in the breathing passages), sinusitis (infection of the sinuses), and pneumonia. Some of these infections may speed up the damage to the immune system from the HIV infection.

Other symptoms may include tiredness (fatigue), headache, muscle and joint pain, fever, diarrhea, and weight loss. Some people have rashes such as seborrheic dermatitis or folliculitis, a rash that looks like acne.

Advanced HIV or AIDS

Advanced HIV or AIDS is diagnosed when the immune function is seriously damaged, often when the patient develops serious opportunistic conditions. These conditions can be major infections or certain cancers. They are called opportunistic because they take advantage of the person's weakened immune system. According to the CDC, any HIV-infected person whose T helper cell count has ever been below 200 cells/mm³ is considered to have AIDS.

A person with AIDS can have more than one opportunistic infection at a time. He or she may also have infections and HIV-related cancers at the same time. These may be cancers such as certain types of lymphoma, Kaposi sarcoma, or invasive cervical cancer. Viral infections may include shingles, cytomegalovirus (CMV) retinitis (infection in the eye), or ulcers of the mouth, anus, or genitals.

Tuberculosis, bacillary angiomatosis, and Mycobacterium avium complex (MAC) are types of bacterial infections that may occur. Other infections can be caused by fungi or parasites, such as Pneumocystis pneumonia or PCP (once called Pneumocystis carinii pneumonia), esophageal candidiasis, coccidioidomycosis, toxoplasmosis, cryptosporidiosis, and histoplasmosis. These are diseases that rarely cause problems in healthy people, but can cause life-threatening illness in people whose immune systems no longer work normally.

Other problems come from HIV directly attacking certain organs rather than by allowing infections by other germs. For example, HIV affects the digestive (gastrointestinal or GI) tract in about 3 out of 5 people. This can cause weight loss, diarrhea, or loss of appetite. One-third to one-half of patients have brain or nervous system (neurologic) symptoms, mostly from infections or cancers, but some are caused by HIV itself. These symptoms can include headache and nerve pain, tingling, numbness, and/or weakness in the hands and feet (peripheral neuropathy). Less often, people may have heart problems or skin problems.

Depression and anxiety are also common in people with HIV. These problems can be caused by many factors, which may include HIV.