infections
Human Immunodeficiency Virus (HIV) Infection
Prevention of HIV Infection
At present, there is no effective HIV vaccine to prevent HIV infection or slow the progression of AIDS in people who are already infected. However, treating people who have HIV infection reduces the risk of their transmitting the infection to other people. Transmission of HIV through its most common routes—sexual contact or sharing of needles—is almost completely preventable. However, the measures required for prevention—sexual abstinence or Prevention and access to clean needles—are sometimes personally or socially unpopular. Many people have difficulty changing their addictive or sexual behaviors, so they continue to put themselves at risk of HIV infection. Also, safer sex practices are not foolproof. For example, condoms can leak or break. Abstain from sexual activity. Use a latex condom for each act of intercourse with an infected partner or a partner whose HIV status is unknown (vaginal spermicides and sponges do not protect against HIV infection). For men engaging in oral sex, withdraw before ejaculation. For men, get circumcised (circumcision reduces a man's risk of being infected with HIV during vaginal sex with an infected woman). For newly monogamous couples, get tested for HIV infection and other sexually transmitted infections (STIs) before engaging in unprotected sexual intercourse. Never share needles or syringes. Wear rubber gloves (preferably latex) when touching body fluids of another person. If accidentally exposed to fluids containing HIV (for example, after a needlestick), seek treatment with antiretroviral medications to prevent infection. Condoms made of latex provide good protection against HIV (as well as other common sexually transmitted infections), but they are not foolproof. Oil-based lubricants (such as petroleum jelly) should not be used because they may dissolve latex, reducing the condom's effectiveness. Other measures can help. For men, circumcision, an inexpensive, safe procedure, reduces the risk of becoming infected during vaginal intercourse with an infected woman by about half. Whether circumcision reduces the risk of HIV infection in other circumstances is unclear. Because circumcision provides only partial protection against HIV infection, people should also use other measures to prevent HIV infection. For example, if either partner has a sexually transmitted infection or HIV infection, it should be treated, and condoms should be used correctly and consistently. People who are likely to come into contact with blood or other body fluids at their job should wear protective latex gloves, masks, and eye shields. These precautions apply to body fluids from all people, not just those from people with HIV, and are thus called universal precautions. Universal precautions are taken for two reasons: People with HIV may not know that they are infected. Viruses that cause other serious disorders (such as hepatitis B and C) can be transmitted by body fluids. Surfaces contaminated with HIV can easily be cleaned and disinfected because HIV is inactivated by heat and by common disinfectants such ashydrogen peroxideand alcohol. Because HIV is not transmitted through the air or by casual contact (such as touching, holding, or dry kissing), hospitals and clinics do not isolate people with HIV infection unless they have another contagious infection. In the United States, the following have almost eliminated transmission of HIV infection by organ transplantation or blood transfusion: Screening donors of organs or blood for risk factors for HIV infection Screening donated blood for HIV Risk is reduced further by asking people with risk factors for HIV infection, regardless of their test results for HIV, not to donate blood or organs for transplantation. However, low-resource countries have not consistently used sensitive HIV screening tests and have not restricted donors. Consequently, transmission by these routes is still a problem in these countries. Pregnant women infected with HIV can transmit the virus to the newborn. The following can help Preventing transmission from infected mother to child : Testing pregnant women to determine whether they are infected with HIV If they are infected, treating them with antiretroviral medications during pregnancy and labor (treatment during labor is especially important) Delivering the baby by cesarean rather than by vaginal delivery After birth, treating the newborn withzidovudine, given intravenously, for 6 weeks If possible, using formula instead of breastfeeding (HIV can be transmitted in breast milk) Taking an antiretroviral medicationbeforebeing exposed to HIV can reduce the risk of HIV infection. Such preventive treatment is called preexposure prophylaxis (PrEP). However, PrEP is expensive and is effective only if people take the medication every day. Thus, PrEP is recommended only for people who have a very high risk of becoming infected, such as people who have a partner who is infected with HIV, people who have sexual behaviors that place them at substantial risk of HIV infection, and people who inject drugs and have injection practices that place them at substantial risk of HIV infection. PrEP may also be recommended for people who engage in high-risk sexual activities, such as the following: Men who have anal sex with men without using a condom Heterosexual men and women who do not regularly use condoms during sex with partners whose HIV status is unknown and who are at increased risk of HIV infection People who use PrEP still need to use other methods to prevent HIV infection, including consistent use of condoms and not sharing needles to inject drugs. People who have been exposed to HIV from a blood splash, needlestick, or sexual contact may reduce the chance of infection by taking antiretroviral medications for 4 weeks. These medications are more effective when they are started as soon as possible after the exposure. Taking two or more medications is currently recommended. Doctors and the person who was exposed typically decide together whether to use these preventive medications. They base the decision on the estimated risk of infection and the possible side effects of the medications. If they do not know whether the source is infected with HIV, they consider how likely the source is to be infected. However, even when the source of the exposure is known to be infected with HIV, the risk of infection after exposure varies, depending on the type of exposure. For example, risk from a blood splash is less than that from a needlestick. Immediately after exposure to HIV infection, what is done depends on the type of exposure: If skin is exposed, it is cleaned with soap and water. Puncture wounds are cleaned with antiseptic. If mucous membranes are exposed, they are flushed with large amounts of water. 