HIV Transmission and Prevention

HIV is a virus that is transmitted through infected blood, semen, vaginal secretions, and breast milk. To enter the body, the virus must come into direct contact with another person’s bloodstream, mucous membrane, or broken skin. HIV is most often transmitted through sexual contact and shared needles.

HIV is often transmitted through anal and vaginal intercourse. While it is possible to acquire HIV while performing oral sex on a man, transmission rates are much lower. It is unlikely that other types of sexual activity, such as oral sex on a woman or manual contact with the genitals, will transmit the virus. The presence of other sexually transmitted infections (STIs), such as syphilis, gonorrhea, or genital herpes, increases the risk of sexual transmission of HIV. Even if an HIV-infected individual has no symptoms, he or she can still transmit the virus.

Many people have contracted HIV through sharing needles, syringes, and other “works” to inject drugs. People may also acquire HIV through the needles used for tattooing and body piercings. Health-care workers may contract HIV through needle-sticks or other accidental exposures on the job. In the past, many people contracted HIV through blood transfusions; today, donated blood is tested and heat-treated and is considered very safe.

HIV can also be transmitted from mother to child during pregnancy or birth (this type of transmission is referred to vertical or perinatal transmission among medical professionals) or through breast-feeding. Vertical transmission is more likely if the mother has a high viral load. Use of antiretroviral drugs, such as AZT or Nevirpine, can reduce the risk of vertical transmission from about 25% to about 5% or less; that is, if a woman responsibly takes her drugs during pregnancy, there is a 95% chance or more that the baby will be born HIV-negative. In the U.S. and other developed countries, it is usually recommended that women with HIV not breast-feed their babies.

There is no evidence that HIV is transmitted through saliva, sweat, tears, or urine. The virus cannot live long outside the human body. HIV is not transmitted through casual or household contact including hugging or kissing, coughing or sneezing, or sharing eating utensils or drinking glasses.

There is currently no vaccine to prevent HIV, although much research in this area is currently underway. If a person has been exposed to HIV, he or she may be eligible for post-exposure prophylaxis (PEP). PEP involves starting anti-HIV drugs within 72 hours of exposure. Although it is unknown whether PEP can help prevent or reduce the severity of HIV disease in people who are exposed to the disease through sex or needle sharing, it has been beneficial to health-care workers who have been accidentally exposed on the job.

HIV Prevention Guidelines

• Do not share needles or other equipment to inject drugs; obtain new needles from a needle exchange. If you must share, make sure to clean needles and syringes thoroughly with bleach before usage.
• Practice safe sex. This includes always using latex condoms and barriers with water-based lubricants. Avoid products that contain nonoxynol-9; this substance can weaken the condom and thus, fail to protect against the disease.
• Tattooists, piercers, and acupuncturists should use new needles for each client.
• Do not share personal items such as toothbrushes.
• Exercise universal precautions in health-care settings, including use of latex gloves.
• Properly dispose of used needles, bandages, and menstrual supplies; make sure to clean and disinfect spilled body fluids.

HIV Disease Progression

Many people with primary or acute (early) HIV infection have no symptoms; that is, they display no symptoms of the disease early on. Others may experience an “acute retroviral syndrome,” which is often characterized by fever, fatigue, headache, and enlarged lymph nodes. These symptoms usually disappear within a week to a month, and are easily mistaken for a bout of the flu. During this initial period, it is possible to transmit HIV easily.

After HIV enters the body, it infects various types of cells. It primarily targets a type of immune system cell called CD4 cells. These cells—also called T-helper cells—play an important role in coordinating the body’s immune defenses. When HIV enters CD4 cells, it uses the cell’s machinery to produce new viral particles (virions), before eventually killing the host cell.

HIV disease progresses slowly, and people with HIV may be asymptomatic (without symptoms) for ten years or longer. Infants and children infected with HIV tend to become ill sooner. As more and more CD4 cells die, the immune system is weakened and the body is less able to fight infections and cancers. As this happens, people may develop symptoms such as swollen lymph nodes, fever, fatigue, and weight loss. These early symptoms may come and go. Some people do not develop symptoms, even without treatment.

Some HIV/AIDS Symptoms

• Swollen lymph nodes
• Fever; night sweats
• Fatigue
• Headache
• Nausea
• Diarrhea
• Loss of appetite
• Weight loss; wasting away
• Skin rashes; red or purple blotches on skin
• Thrush; vaginal yeast infections; fungal nail infection
• Mental impairment; memory loss

AIDS is the advanced stage of HIV disease. Once the CD4 count falls below 200 (and particularly below 50), people become susceptible to a variety of opportunistic illnesses (OIs). These are infections or cancers that usually do not cause symptoms in healthy people, but may cause serious illness in people with compromised immune systems. There are more than 20 AIDS-defining conditions.

HIV positive people with CD4 cell counts below 200 are classified as having AIDS even if they do not have OIs. The classic symptoms of AIDS—such as persistent diarrhea, night sweats, wasting, skin conditions, and mental impairment—are usually due to OIs. (However, as described below, the drugs used to treat HIV can themselves cause side effects such as nausea, diarrhea, and skin rash.) Children with HIV may experience delayed development or “failure to thrive.” Diseases such as cervical cancer, hepatitis C, herpes, and tuberculosis may be much more aggressive in people with HIV, and are considered AIDS-related illnesses even though they also occur in people without HIV.

In recent years, the incidence of OIs has fallen due to improved anti-HIV treatments. Effective treatment can keep HIV under control and help prevent the loss of CD4 cells. With appropriate treatment, some people may be able to hold off late-stage disease and the development of OIs indefinitely.

HIV Treatment

Since 1997, there are medicines which delay the progress of HIV and weaken its effects. A combination (’a cocktail’) of drugs usually works best. People with HIV sometimes need to take many pills a day, as they are taking pills both for the disease and its related side-effects and illnesses. While the side-effects can be bad, people living with HIV can now live long and relatively healthy lives. However, it is important to remember that no vaccine against HIV (currently) exists and there are no drugs that cure AIDS.

Medication in Developing Countries

Less than 5% of all people with HIV/AIDS in developing countries have access to the cocktail of life-saving drugs. The medicines are very expensive and the governments of these countries often cannot afford to pay the pharmaceutical companies for them