amfAR, The Foundation for AIDS Research

Basic Facts About HIV/AIDS

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What is amfAR?


Among its accomplishments, amfAR provided the essential early funding for research that contributed to the development of four of the six classes of lifesaving HIV medications, and pioneered early studies that eventually led to the virtual elimination of mother-to-infant HIV transmission in many parts of the world.

Research conducted by amfAR-funded scientists is bringing us closer to answering questions about HIV that may eventually lead to a vaccine, new drug therapies, and even a cure.

For a monthly update on amfAR’s programs and activities, sign up to receive amfAR e-News.

Understanding HIV/AIDS

Transmission and Testing

Protecting Yourself   

Treatment and the Search for Solutions  

Join the Fight

What is HIV?

HIV stands for human immunodeficiency virus.


What is AIDS? 

AIDS stands for acquired immunodeficiency syndrome. 

As HIV grows in an infected person, it damages or kills specific immune cells, weakening the immune system and leaving the person vulnerable to infections and illnesses ranging from pneumonia to cancer.  Only when someone with HIV begins to experience one or more of these conditions or loses a significant amount of immune cells are they diagnosed with AIDS.

How do I know if I’m infected?


Can I tell whether someone has HIV or AIDS? 


How quickly do people infected with HIV develop AIDS? 

In some people, AIDS develops soon after infection with HIV. But many people do not develop symptoms for 10 to 12 years, and a few remain symptom-free for much longer.  Early detection and treatment plays an important role in slowing the progression to AIDS and helps many people with HIV lead relatively normal lives. 

How many people are living with HIV/AIDS? 

There are now roughly 34 million people living with HIV or AIDS worldwide. Most of them do not know they are infected and may be spreading the virus to others. In the U.S., more than one million people are living with HIV/AIDS, and approximately 50,000 Americans become newly infected with HIV each year. It is estimated that one-fifth of all people with HIV in the U.S. do not know they are infected.

How is HIV transmitted? 






How is HIV not transmitted? 


In the U.S., screening the blood supply for HIV has virtually eliminated the risk of infection through blood transfusions. And because of strict medical precautions, you cannot get HIV from giving blood at a blood bank or other established blood collection center.

There have been no documented cases of HIV transmission through other body fluids such as sweat, tears, vomit, and urine. Mosquitoes, fleas, and other insects do not transmit HIV.

Are some people at greater risk of HIV infection than others? 

HIV does not discriminate.  It is not who you are but what you do that determines whether you are at risk of becoming infected with HIV.

In the U.S., the epidemic has taken an especially heavy toll on some groups:  

More new HIV infections occur among young people ages 13 to 29 than any other age group.

More than 25 percent of Americans living with HIV are women.  In fact, women are at least twice as likely to contract HIV through vaginal sex with infected males than vice versa.

More than half of all new HIV infections occur in gay men and other men who have sex with men (MSM), even though MSM represent only two percent of the U.S. male population. 

African Americans, who comprise only 14 percent of the population, account for almost half of all new HIV infections.

Should I get tested? 

If you are sexually active or are injecting drugs, you should get tested as soon as possible.

Here’s why:

  • If you are HIV positive, you will be able to take the precautions necessary to protect others from becoming infected, such as consistently using condoms.  Treatment can also reduce your risk of infecting others.
  • If you are HIV positive and pregnant, you can take medications to significantly reduce the risk of infecting your infant. 

How can I get tested?  






If you are sexually active, protect yourself against HIV by practicing safer sex. When used properly and consistently, condoms are close to 99 percent effective in preventing the transmission of HIV. But remember:

Use protection each and every time you have sex and limit the number of sexual partners you have.

Use only latex condoms.  A dental dam─a square of latex─is recommended for oral−genital and oral−anal sex.


Limit the use of alcohol or recreational drugs, which can impair judgment.

Is there a link between HIV and other sexually transmitted infections? 

Practicing safer sex will help you avoid other sexually transmitted infections (STIs), which can increase your risk of acquiring and transmitting HIV. HIV-positive individuals who are infected with another STI are more likely to transmit the virus through sex.  And HIV-negative individuals who are infected with another STI are up to five times more likely to acquire HIV through sexual contact with an HIV-positive person.

How can I avoid acquiring HIV from a contaminated syringe? 

If you are injecting drugs of any type, including steroids, do not share syringes or other injection equipment with anyone else. Detailed HIV prevention information for injecting drug users is available from the CDC’s National Prevention Information Network at 1-800-CDC-INFO (1-800-232-4636) or online at

Should I be concerned about HIV if I am getting a tattoo or piercing? 

If you are planning to get a tattoo or have any part of your body pierced, be sure to see a qualified professional who uses sterile equipment. Single-use instruments that penetrate the skin should be used once, then disposed of.  Reusable instruments that penetrate the skin should be thoroughly cleaned and sterilized between clients.

Are there treatments for HIV/AIDS? 

Today, a number of drugs are available to treat HIV/AIDS. Many people living with HIV take these drugs in combination—a regimen known as highly active antiretroviral therapy (HAART). When taken as directed, anti-HIV treatment can reduce the amount of HIV in the bloodstream to very low levels and sometimes enable the body’s immune cells to rebound to normal levels.  The number of AIDS-related deaths in the U.S. has dropped dramatically because of widely available, effective treatments.

Even when patients respond well to HAART, however, it does not cure HIV.  Treatment does not work for everyone. Anti-HIV drugs are very expensive and often cause serious side effects.  And because HIV mutates constantly, the virus often develops resistance and the medications become ineffective.

Is there a vaccine to prevent HIV infection?

Despite continued intensive research, experts believe it will be many more years before we have a safe, effective, and affordable AIDS vaccine. Until then, other HIV prevention methods, such as practicing safer sex and using sterile syringes, are necessary.

Is there a cure for AIDS? 

While new medications are helping many infected people live longer, healthier lives, AIDS is still a fatal disease for which there is no cure. Nonetheless, recent scientific advances have created a groundswell of optimism that a cure could be found.

amfAR has long been a leader in cure-focused research and allocates more than half of its research grants to cure-focused studies.  

Where can I get more information about HIV/AIDS?  

There are many valuable sources of HIV/AIDS information, including:

  • amfAR:
  • The Centers for Disease Control and Prevention:  
  • The Kaiser Family Foundation’s HIV/AIDS information section:
  • Your state or local health department
  • Your local AIDS service organization
  • Joint United Nations Programme on HIV/AIDS (UNAIDS):

How can I help fight HIV/AIDS? 


  • Volunteer with your local AIDS service organization.
  • Talk with your friends and family about HIV/AIDS.
  • Sponsor an AIDS education event or fundraiser with your local school, community group, or religious organization.
  • Speak out against AIDS-related stigma and discrimination.
  • Support continued research into better treatments, new prevention methods, and ultimately a cure for AIDS by making a donation to amfAR.