Many people (not just kids, but adults, too) don't understand how HIV and AIDS are related, even though they hear these two words used together all the time.

HIV stands for human immunodeficiency (say: im-yuh-noh-di-fish-un-see) virus. AIDS stands for acquired immunodeficiency syndrome. HIV is actually the virus that causes the disease AIDS.

HIV Hurts the Immune System

People who are HIV positive have been tested and found to have signs of the human immunodeficiency virus in their blood. HIV destroys part of the immune (say: ih-myoon) system. Specifically, it affects a type of white blood cell called the T lymphocyte (say: lim-fuh-site), or T cell. T cells are one type of "fighter" cell in the blood that help the body fight off all kinds of germs and diseases.

After HIV enters the body, it piggybacks onto a T cell and works its way inside of that cell. Once inside, the virus completely takes over the T cell and uses it as a virus-making factory to make a lot of copies of itself. The newly made viruses then leave the T cell and go on to infect and destroy other healthy T cells as they continue to multiply inside the body. T cells invaded by the virus can no longer properly fight infections.

Someone who is infected with the virus is called HIV positive. But it may take years for the virus to damage enough T cells for that person to get sick and develop AIDS. Although the HIV-positive person may feel fine, the virus is silently reproducing itself and destroying T cells.

However, thanks to new medications, someone infected with HIV can stay relatively healthy and symptom-free for many years. These medications are very expensive and not available to everyone in the world.

When the person's immune system has weakened and more of the blood's T cells have been destroyed by the virus, the person can no longer fight off infections. This is when he or she gets very sick. A doctor diagnoses someone with AIDS when the person has a very low number of T cells or shows signs of a serious infection.

How Many People Have HIV/AIDS?

Since the discovery of the virus almost 30 years ago, millions of people throughout the world have been infected with HIV. Most are adults, but some kids and teens have HIV, too. In the world today, AIDS remains an epidemic (say: eh-puh-deh-mik), which means that it affects a large number of people and continues to spread rapidly.

Right now, about 40 million people in the world are living with HIV infection or AIDS. This estimate includes 37 million adults and 2.5 million children. In the United States alone, more than 1 million people are living with HIV.

How Is HIV Spread?

HIV infection isn't like a cold or the flu. A kid cannot get HIV by riding a school bus with or visiting the home of someone who has HIV, or by holding that person's hand. HIV is passed only through direct contact with another person's body fluids, such as blood.

The majority of people in North America get infected with HIV by:

• sexual contact
• sharing needles or syringes (used to inject drugs or other things) with another person

Other ways of getting HIV:

• An infected pregnant woman passes it to her unborn child (this can be prevented by treating the mother and child around the time the baby is delivered).
• A person has a blood transfusion (say: trans-fyoo-zhun). But in North America today, all donated blood is tested for HIV, so the risk of getting HIV that way is less than 1 in a million.

What Are the Symptoms of HIV/AIDS?

It's important to know that you can't tell that someone has HIV just by what he or she looks like. Most people don't feel any different after they are infected with HIV. In fact, infected people often do not experience symptoms for years. Some develop flu-like symptoms a few days to a few weeks after being infected, but these symptoms usually go away after several days.

If untreated, an HIV-positive person will eventually begin to feel sick. The person might begin to have swollen lymph nodes, weight loss, fevers that come and go, infections in the mouth, diarrhea, or he or she might feel tired for no reason all of the time. Eventually, the virus can infect all of the body's organs, including the brain, making it hard for the person to think and remember things.

When a person's T cell count gets very low, the immune system is so weak that many different diseases and infections by other germs can develop. These can be life threatening. For example, people with AIDS often develop pneumonia (say: nu-mo-nyah), which causes bad coughing and breathing problems. Other infections can affect the eyes, the organs of the digestive system, the kidneys, the lungs, and the brain. Some people develop rare kinds of cancers of the skin or immune system.

Most of the children who have HIV got it because their mothers were infected and passed the virus to them before they were born. Babies born with HIV infection may not show any symptoms at first, but if they are not treated, the progression of AIDS is often faster in babies than in adults. Doctors need to watch them closely. Kids who have HIV or AIDS may learn more slowly than healthy kids and tend to start walking and talking later.

How Are HIV/AIDS Diagnosed?

Someone can be infected with HIV without even knowing it. So doctors recommend testing for anyone who might have been exposed to the virus, even if the chance seems very small. Doctors test a person's blood or saliva to find out if he or she is infected with HIV.

People who are HIV positive need to have additional blood tests every so often. The doctor will want to see how many T cells the person has. The lower the T cell count, the weaker the immune system and the greater the risk that someone will get very sick.

How Are HIV/AIDS Treated?

Right now there is no cure for HIV or AIDS, but new medicines can help people live long and healthy lives like people with other chronic diseases (such as diabetes).

Scientists are also researching vaccines that one day might help to prevent HIV infection, but it's a very tough assignment and no one knows when these vaccines might become available.

Can HIV/AIDS Be Prevented?

People can help stop the spread of HIV by practicing safe sex and by not sharing needles or syringes.

Health care workers (such as doctors, nurses, and dentists) help prevent the spread of HIV by wearing protective gloves when working on a patient.

Hospitals have strict procedures for handling samples of blood and other body fluids to prevent others from coming in contact with HIV.

Living With HIV/AIDS

New drugs make it possible for people who are HIV positive to live for years without getting AIDS. They can work or go to school, make friends, hang out, and do all of the things other people can do. They will have to take certain medicines every day and see their doctors pretty often, and they may get sick more than other people do because their immune systems are more fragile.

Even though they may look OK, people who are HIV positive may sometimes feel scared, angry, unhappy, or depressed. They may feel afraid that the people at work or school, or their friends or family could find out and start treating them differently. If you know someone who is HIV positive, treat him or her just like any other friend.

Hope for an HIV-Free Future

Maybe one day, with time and research, a cure for HIV infection will be found and AIDS will no longer exist. Until then, the smartest thing to do is to know the facts and avoid putting yourself at risk.

If you have more questions about HIV or AIDS, talk to an adult you trust — a parent, doctor, school nurse, or guidance counselor. Don't depend only on your friends for information about HIV and AIDS because they may not know all the right answers.

Reviewed by: Nadia Dowshen-Atanda, MD
Date reviewed: February 2012