What are AIDS and HIV?

AIDS stands for acquired immunodeficiency syndrome, a condition first reported in the United States in 1981, that has since become a major worldwide epidemic.

AIDS is caused by HIV (human immunodeficiency virus). By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers. The term AIDS applies to the most advanced stages of HIV infection.

How is HIV spread?

There are several common ways that HIV can be passed from person to person, including:

• Having unprotected sex with someone who is infected
• Using needles or syringes that have been used by people who are infected
• Receiving infected blood products or transplanted organs (Since 1985, the United States actively tests all donated blood for HIV; therefore, the risk of getting HIV in this way in the United States is now extremely low.)
• Transmission from mother to child – An infected mother may pass the virus to her developing fetus during pregnancy, during birth, or through breastfeeding.

If you have a sexually transmitted disease, you may be at higher risk for getting infected with HIV during sex with an HIV-infected partner.

There is no evidence that HIV is spread by contact with saliva or through casual contact, such as shaking hands or hugging, or the sharing of food utensils, towels and bedding, swimming pools, telephones, or toilet seats. HIV is not spread by biting insects such as mosquitoes or bedbugs.

What is the treatment for HIV/AIDS?

Although when AIDS first appeared there were few treatments, researchers have now developed drugs that can help fight both HIV and the related infections and cancers that come with it. Treatment advances have improved the survival rates and decreased progression of HIV disease in developed countries like the United States, where antiretroviral drugs are available.

Additional treatment information is available from the National Institute of Allergy and Infection Diseases at NIH. The NIH is currently conducting many clinical trials related to HIV/AIDS to test treatments and therapies. These trials are sponsored and co-sponsored by various Institutes, including the NICHD.

The NICHD supports and conducts research related to HIV/AIDS in specific groups of people, including pregnant and non-pregnant women, infants and children, and adolescents and young adults. The information below applies to those groups.

How does HIV/AIDS affect women?

According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), 19.2 million women are living with HIV/AIDS throughout the world. In many countries, the rate of HIV infection in women is rising faster than in any other group.

Worldwide, more than 80 percent of HIV infections are spread by heterosexual sex (vaginal intercourse); women are particularly at risk of contracting HIV through this type of contact. HIV is increasing most dramatically among African American and Hispanic women.

Although most of the signs and symptoms of HIV infection are similar in men and women, some are more specific to females. For example:

• Vaginal yeast infections may be chronic, more severe, and difficult to treat in women with HIV infection than in women who are uninfected.
• Pelvic inflammatory disease, an infection of the female reproductive organs, may also be more frequent and severe in women with HIV infection.
• Human papillomavirus (HPV) infections, which cause genital warts, may occur more frequently in HIV-infected women, and can lead to pre-cancerous lesions of the cervix or cancer of the cervix.

The NICHD, along with other Institutes, supports studies to determine what aspects of HIV are specific to women and the best treatments for these symptoms.

How does HIV affect pregnant women and infants?

Women can give HIV to their babies during pregnancy, while giving birth, or through breastfeeding.

But, there are effective ways to prevent the spread of mother-to-infant transmission of HIV:

• Taking anti-HIV drugs during pregnancy—either a drug called zidovudine or AZT alone or in combination with other drugs called highly active antiretroviral therapy (HAART)—a mother can significantly reduce the chances that her baby will get infected with HIV.
• Delivering the baby by cesarean section, and doing so before the mother’s uterine membranes rupture naturally, reduces transmission that may occur during the birth process. Use of anti-HIV drugs during pregnancy and delivery, combined with a cesarean section in women with certain levels of HIV in their blood, can reduce the chance that the baby will be infected to less than 2 percent.
• Avoidance of breastfeeding by an HIV-infected mother. HIV can be spread to babies through the breast milk of mothers infected with the virus. The American Academy of Pediatrics recommends that, in countries such as the United States, where infant formula is safe and is often available and affordable, HIV-infected women feed their infants commercially available formula instead of breastfeeding.

Approximately one-fourth to one-half of all untreated pregnant women infected with HIV will pass the infection to their babies. HIV infection of newborns is very rare in the United States because women are tested for HIV during pregnancy, and women with HIV infection receive anti-HIV drugs during pregnancy, cesarean delivery if their HIV blood levels are high, and are advised not to breastfeed their infants.

How does HIV affect children and adolescents?

It is estimated that approximately 10,000 children are living with HIV infection in the United States. In the United States, the number of infants born with HIV infection has dramatically decreased from about 2,000 a year to fewer than 200 a year due to identification of HIV infection in pregnant women and use of anti-HIV drugs during pregnancy, cesarean delivery, and avoidance of breastfeeding.

In contrast to the United States, mother-to-child transmission in developing countries remains a major problem; about 700,000 infants are newly infected with HIV each year because most women are not screened for HIV during pregnancy, anti-HIV drugs are not available, and safe alternatives to breastfeeding are not available.

Prior to 1985, when screening of the nation's blood supply for HIV began, some children as well as adults were infected through transfusions with blood or blood products contaminated with HIV, but this is now rare in the United States.

In contrast to the dramatic decrease in mother-to-child transmission of HIV infection, the number of cases of HIV infection in adolescents and young adults continues to increase in the United States. About one-third to one-half of new HIV infections in the United States are among adolescents and young adults.

Most HIV-infected adolescents and young adults are exposed to the virus through unprotected sex; some teens and young adults are also infected through injection drug use. In addition, an increasing number of children who were infected as infants are now surviving to adolescence.