HIV (human immunodeficiency virus) infects 40,000 people in the U.S. each year. If left untreated, HIV infection can lead to AIDS (acquired immune deficiency syndrome).

HIV works by entering a type of white blood cell called CD4+ T-cells (or “helper” T-cells). T-cells contribute to the body’s defenses by activating and directing other immune cells. When HIV enters a T-cell, it reproduces itself and kills the T-cell in the process. As the virus spreads in the body, more and more T-cells are killed. The outcome is a weakened immune system. This can lead to “opportunistic infections” which take advantage of the weakened immune system to cause more serious problems than they would in an uninfected person.

Transmission
HIV is primarily transmitted through vaginal and anal sex. It can also be transmitted by sharing needles, from mother to child during pregnancy or breastfeeding, and from direct exposure to infected fluids (an accidental needle stick in a lab).

Symptoms
Some people experience flu-like symptoms when they first get infected with HIV, such as fever, muscle aches, fatigue, headaches, and swollen glands. After the initial infection, there are usually no symptoms unless the infection progresses to AIDS.

Complications
Without treatment, HIV infection can lead to AIDS. The symptoms of AIDS vary, but may include severe fatigue, rapid weight loss, frequent infections (e.g. yeast infections, diarrhea, herpes outbreaks), fevers and/or night sweats, coughing and shortness of breath, and mental disorientation. AIDS can lead to death if opportunistic infections overwhelm the body’s weakened immune system.

Diagnosis
HIV infection can be diagnosed with a blood, urine, or oral swab test. The test looks for antibodies to HIV, rather than the virus itself. Because it can take four weeks to six months, with an average of three to six months for antibodies to develop, you may get a false negative result if you have had any risk of exposure in the past six months. If the result is positive, you should talk with a clinician about how to stay healthy and about whether medication would be appropriate. You should also avoid transmitting the virus to others by using the prevention strategies discussed below.

The Tang Center offers confidential testing (blood test), which means that the test result goes into a confidential section of the medical record. This medical record can only be released with your permission, or in certain circumstances like a legal subpoena. There are now many laws protecting HIV-infected people from discrimination. One exception is that if you obtain health insurance as an individual (i.e. not through your employer), the insurance company is allowed to charge you a higher rate or refuse to insure you. If you have concerns about taking a confidential test, there are many organizations that offer anonymous testing where your name is never connected with the results (you get a special code instead).

AIDS is diagnosed when an HIV-infected person has experienced a “defining” opportunistic infection, or has a CD4+ T-cell count below 200 cells/microliter or below 14% of all lymphocytes.

Treatment
Although HIV infection cannot be cured, there is treatment available to slow or prevent the progression to AIDS.  Treatment is commonly started when a person’s CD4+ T-cell count drops to 350 cells/microliter (before a diagnosis of AIDS).

Prevention
The following strategies can help reduce the risk of infection:
PrEP (Pre-exposure prophylaxis)
• Abstinence
• Mutual monogamy
• Condoms, dental dams, or other barrier methods
• Avoiding injection drug use, and not sharing needles or other equipment if you do use
• Avoiding sharing personal items that may have blood on them, such as toothbrushes and razors
• If you are HIV-infected, you cannot donate blood.