How Is HIV Transmitted?
HIV is transmitted through direct contact with the blood or body fluid of someone who is infected with the virus.
The three main ways the HIV virus is passed to a very young child are:
- while the baby develops in the mother's uterus (intrauterine)
- at the time of birth
- during breastfeeding
Among teens, the virus is most commonly spread through high-risk behaviors including:
- unprotected sexual intercourse
- sharing needles used to inject drugs or other substances (including contaminated needles used for injecting steroids and tattooing and body art)
In very rare cases, HIV has also been transmitted by direct contact with an open wound of an infected person (the virus may be introduced through a small cut or tear on the body of the healthy person) and through blood transfusions. Since 1985, the U.S. blood supply has been carefully screened for HIV.
Signs and Symptoms of HIV
Although there may be no immediate physical signs of HIV infection at birth, signs of the infection might appear within 2 to 3 months after a child is born. Kids who are born with HIV can develop opportunistic infections, which are illnesses that can develop in weakened immune systems such as Pneumocystis carinii pneumonia (PCP). A child with HIV may also get more severe bouts of other common childhood infections, such as Epstein-Barr virus (EBV) infection, which generally causes mild illness in most kids. In developing countries, tuberculosis has been a particularly common problem and often the cause of death of children and adults.
A baby born with HIV infection most likely will appear healthy. But sometimes, within 2 to 3 months after birth, an infected baby may begin to appear sick, with poor weight gain, repeated fungal mouth infections (thrush), enlarged lymph nodes, enlarged liver or spleen, neurological problems, and multiple bacterial infections, including pneumonia.
Teens and young adults who contract HIV usually show no symptoms at the time of infection. In fact, it may take up to 10 years or more for symptoms to show. During this time, they can pass on the virus without even knowing they have it themselves. Once the symptoms of AIDS appear, they can include rapid weight loss, intense fatigue, swollen lymph nodes, persistent diarrhea, night sweats, or pneumonia. They, too, will be susceptible to life-threatening opportunistic infections.
Diagnosing HIV Infections and AIDS
Every pregnant woman should be tested for HIV to have a better chance of preventing transmission to her unborn child.
If a woman knows she is HIV-infected and already has children, then it is recommended that all of her children be tested for HIV. Even if she has older children and they seem healthy, they could still have an HIV infection if she was already HIV-positive at the time they were born. A blood test is needed to know for sure.
However, when a new baby is born to an HIV-infected mother, there is no immediate way to know whether the baby is infected with the virus. This is because if the mother is infected, an ELISA test to check for HIV antibodies in a newborn's blood will almost always be positive, too. Babies will have their HIV-infected mother's antibodies (which are passed to the baby through the placenta) even if they are not truly infected with HIV. These babies may remain HIV-antibody positive for up to 18 months after birth, even if they are not actually infected.
Infants who are not actually infected with the virus (but are born to HIV-positive mothers) will not make their own antibodies; the HIV antibodies that came from their mothers will gradually disappear from their blood before they reach 2 years of age. Any blood tests performed after this point will likely be HIV-negative. Infants who are infected with HIV from their mothers will begin to make their own HIV antibodies and will generally remain HIV-positive after 18 months of age.
The most accurate diagnosis of HIV infection in early infancy comes from tests that show the presence of the virus itself (not HIV antibodies) in the body. These tests include an HIV viral culture and PCR (polymerase chain reaction), a blood test that looks for the DNA of the virus.
Older children, teens, and adults are tested for HIV infection by a blood test known as an ELISA test, which detects the presence of HIV antibodies in the blood. Antibodies are specific proteins that the body produces to fight infections; HIV-specific antibodies are produced in response to infection with HIV. Someone with antibodies against HIV is said to be HIV-positive. If the ELISA test is positive it is always confirmed by another test called a Western blot. If both of these tests are positive, the patient is almost certainly infected with the HIV virus.
Treating AIDS and HIV
There have been two major advances in the treatment of HIV/AIDS over the last 20 years. One is the development of drugs that inhibit the virus's growth, preventing or delaying the onset of AIDS and allowing people living with HIV to remain free of symptoms longer. The other is the development of medications that have proven very important in reducing the transmission of the virus from an HIV-infected mother to her child.
Across the United States, there have been only a handful of reported cases where HIV infection was contagious from a child to another person. All of those cases involved direct blood contact within a household. The typical baby secretions (urine, drool, spit up, vomit, feces, etc.) do not seem to transmit the virus, so routine care of babies with HIV is considered safe.
Despite widespread concerns, there are no reported transmissions of the HIV virus within a school or child-care setting. Because the danger in transmitting HIV involves direct contact with blood, personnel at schools and child-care programs should routinely use gloves when any child has a cut, scrape, or is bleeding.
HIV is not spread through:
- casual contact, such as hugs or handshakes
- drinking glasses
- mosquitoes or other insects
- toilet seats