Dr. Sabrina Kendrick, Director of the Ruth M. Rothstein CORE Center, talks about HIV

• What is HIV?

  HIV stands for human immunodeficiency virus. This is the virus that causes AIDS. HIV is different from most other viruses because it attacks the immune system. The immune system gives our bodies the ability to fight infections. HIV finds and destroys a type of white blood cell (T cells or CD4 cells) that the immune system must have to fight disease.

• What are the statistics for HIV?

  In 2006, an estimated 56,300 individuals were infected with HIV.CDC estimates that about 1 million people in the United States are living with HIV or AIDS. About one quarter of these people do not know that they are infected: not knowing puts them and others at risk.

• How is HIV transmitted?

  HIV is primarily found in the blood, semen, or vaginal fluid of an infected person. HIV is transmitted in 3 main ways:

  Having sex (anal, vaginal, or oral) with someone infected with HIV

  Sharing needles and syringes with someone infected with HIV

  Being exposed (fetus or infant) to HIV before or during birth or through breast feeding

  HIV is not transmitted through day-to-day activities such as shaking hands, hugging, or a casual kiss. You cannot become infected from a toilet seat, drinking fountain, doorknob, dishes, drinking glasses, food, or pets. You also cannot get HIV from mosquitoes.

• What are the symptoms of HIV?

  For more detailed information, view the HIV Symptoms page.

• How do you test for HIV?

  Once HIV enters the body, the body starts to produce antibodies—substances the immune system creates after infection. Most HIV tests look for these antibodies rather than the virus itself. There are many different kinds of HIV tests, including rapid tests and home test kits.

• What is the testing "Window Period" for HIV infection?

  The "window period" is the time it takes for a person who has been infected with HIV to react to the virus by creating HIV antibodies. This is called seroconversion.

  During the window period, people infected with HIV have no antibodies in their blood that can be detected by an HIV test, even though the person may already have high levels of HIV in their blood, sexual fluids, or breast milk.

  Here is what the CDC says about the window period:

  "Antibodies generally appear within three months after infection with HIV, but may take up to six months in some persons." This CDC definition of a three to six month window period has been commonly used for a number of years.

  What does this mean for you?

  The three month window period is normal for most of the population. Many people will have detectable antibodies in three or four weeks. Very, very rarely (i.e., only a few cases ever), a person could take six months to produce antibodies.

  You may be anxious to be tested soon after an encounter which you perceive to be risky (for a discussion of what behaviors put you at risk for HIV and which ones do not, see the section on How HIV Is Spread). You want to know: can I be antibody tested without waiting three months? How accurate is the test after, say, six weeks? Unfortunately, we simply don't know. Think about this: if you got a negative test at six weeks, would you believe it? Would it make you less anxious? If so, then go for it. But to be certain, you will need to be tested again at three months. Some test centers may recommend testing again at six months, just to be extra sure.

  Although HIV may not be detected by a test during the window period, HIV can be transmitted during that time. In fact, individuals are often most infectious during this time (shortly after they have been exposed to HIV).

• Is there a vaccine or treatment for HIV?

  There is no cure for AIDS at this time. However, a variety of treatments are available that can help keep symptoms at bay and improve the quality of life of those who have already developed symptoms.

  Antiretroviral therapy suppresses the replication of the HIV virus in the body. A combination of several antiretroviral agents, termed highly active antiretroviral therapy (HAART), has been highly effective in reducing the number of HIV particles in the blood stream, as measured by a blood test called the viral load. Preventing the virus from replicating can help the immune system recover from the HIV infection and improve T-cell counts.

  HAART is not a cure for HIV, and people on HAART with suppressed levels of HIV can still transmit the virus to others through sex or sharing of needles. But HAART has been enormously effective for the past 10 years. There is good evidence that if the levels of HIV remain suppressed and the CD4 count remains high (above 200 cells/mL), life can be significantly prolonged and improved.

  However, HIV may become resistant to HAART in patients who do not take their medications on schedule every day. Genetic tests are now available to determine whether a particular HIV strain is resistant to a particular drug. This information may be useful in determining the best drug combination for each individual, and adjusting the drug regimen if it starts to fail. These tests should be performed any time a treatment strategy begins to fail, and prior to starting therapy.

  When HIV becomes resistant to HAART, other drug combinations must be used to try to suppress the resistant strain of HIV. There are a variety of new drugs coming out on the market for the treatment of drug-resistant HIV.

  Treatment with HAART has complications. HAART is a collection of different medications, each with its own side effects. Some common side effects are nausea, headache, weakness, malaise (a general sick feeling), and fat accumulation on the back ("buffalo hump") and abdomen. When used for a long time, these medications increase the risk of heart attack by increasing the levels of fat and glucose in the blood.

  Any doctor prescribing HAART should carefully watch the patient for possible side effects associated with the combination of medications the patient takes. In addition, routine blood tests measuring CD4 counts and HIV viral load (a blood test that measures how much virus is in the blood) should be taken every 3-4 months. The goal is to get the CD4 count as close to normal as possible, and to suppress the HIV amount of virus in the blood to an undetectable level.

  Other antiviral medications are being investigated. In addition, growth factors that stimulate cell growth, such as Epogen (erthythropoetin) and G-CSF are sometimes used to treat anemia and low white blood cell counts associated with AIDS.

  Medications are also used to prevent opportunistic infections (such as Pneumocystis uiroveci pneumonia) if the CD4 count is low enough. This keeps AIDS patients healthier for longer periods of time. Opportunistic infections are treated when they happen.

SOURCE: Centers for Disease Control and Prevention (CDC) www.cdc.gov