What Is HIV?


Human immunodeficiency virus, or HIV, is a virus that attacks the body's infection-fighting immune system. More than one million people in the United States live with HIV, and one in seven of them don't know they have it. The virus is found in the blood and body fluids of people infected with HIV.

Without treatment, HIV can lead to AIDS (acquired immunodeficiency syndrome). At the start of the AIDS epidemic in the 1980s, people who were infected with HIV quickly progressed to this serious disease. But today's treatments help lower the amount of virus in the blood so people who are HIV-positive can live healthier lives.

HIV can affect anyone, but gay and bisexual men are particularly vulnerable, accounting for more than two-thirds of all newly diagnosed cases in the U.S. Black and Hispanic people are disproportionately affected.

HIV is commonly transmitted through sexual contact or the use of shared needles, syringes, or other materials used for injecting drugs. There's no cure for HIV, but medications can keep the infection from worsening.

What Is AIDS?

AIDS, short for acquired immunodeficiency syndrome, is the most advanced stage of HIV. It refers to the set of symptoms a person develops when the immune system is too weak to fight off infection.

People with AIDS have severe immune-system damage. This can be determined in two ways. One is by the number of CD4 cells in a sample of blood. (A CD4 cell is a type of white blood cell that attacks infection.) HIV destroys CD4 cells, so a person's count declines. AIDS is diagnosed when the CD4 count falls below 200 cells per cubic millimeter of blood. (A healthy person has a count of between 500 and 1,500.)

Another sign of AIDS is when the person infected with HIV develops one or more infections, regardless of their CD4 count, that is more common or more severe among people with weakened immune systems. These infections are called opportunistic infections.

Without treatment, HIV gradually destroys the immune system. The time it takes for HIV to progress and become AIDS varies from person to person. On average, it takes 10 years. Advances in treatment have helped millions stave off symptoms of AIDS.

Signs and Symptoms of HIV

HIV symptoms are not a reliable indicator of infection. Some people may feel sick within the first four weeks of infection, while others may show no symptoms for 10 years or more. Plus, the early signs of HIV are much like any other infection. So the only way to know whether you have it is to get tested.

An estimated 40 to 90 percent of people with HIV experience flu-like symptoms within two to four weeks of being infected, according to the U.S. Centers for Disease Control and Prevention (CDC). Some people may not feel sick at all in the early stage of HIV, also known as acute infection. HIV may not even show up on some diagnostic tests at this early stage. Yet this is the time when the virus is most contagious.

Early symptoms of HIV, meaning signs that occur within the first six months of infection (including the first two to four weeks) may include fever, muscle aches, fatigue, swollen lymph nodes, or some combination of flu-like symptoms. HIV rash can be a symptom of infection or a side effect of medication.

Symptoms may last a few days to a few weeks and can include:

  • Fever
  • Chills
  • Sore throat
  • Mouth ulcers
  • Headache
  • Rash
  • Night sweats
  • Fatigue
  • Muscle aches
  • Diarrhea
  • Swollen lymph nodes

After the early stage of infection, people with HIV may have mild or no symptoms. Even without treatment, this chronic stage of the disease can last for a decade, while people taking medications for their HIV can live in this stage even longer. However, the virus remains active and HIV is still contagious at this stage. Even people who don't have symptoms can transmit the infection to others. Treatment reduces the amount of virus in the blood, making transmission less likely.

Without treatment, HIV eventually batters the immune system to the point that people living with this infection are prone to all sorts of serious illnesses. Late-stage HIV symptoms may include:

  • Rapid weight loss
  • Recurring fever
  • Extreme fatigue
  • Persistent cough
  • Mouth, anus, and/or genital sores
  • Swollen lymph glands in the armpits, groin, and/or neck
  • Memory loss, depression, or other neurologic issues
  • Chronic diarrhea
  • Blotchy skin
  • Pneumonia
  • Night sweats

What Causes HIV?

HIV attacks and kills a specific type of white blood cell, called a CD4 cell. Normally, these cells guard against infection. But, when HIV enters the bloodstream, the virus uses these cells to make copies of itself and spread throughout the body.

The process takes place over several stages, known as the "HIV life cycle." First, HIV binds to the surface of the CD4 cell and then fuses with the cell membrane to enter the cell. From there, it converts its genetic material (RNA) into DNA, allowing the virus to enter the cell nucleus. There, HIV inserts its viral DNA into the DNA of the CD4 cell and produces HIV proteins that can be used to make more HIV. Finally, those new proteins and new HIV RNA are pushed out of the cell, forming new HIV capable of infecting other cells, and the process begins all over again.

HIV is believed to have existed in the U.S. since the 1970s. Scientists trace its roots to Central Africa. They believe a virus found in chimpanzees jumped species and mutated into HIV sometime in the late 1800s when humans hunting chimps for meat were exposed to the animals' blood. U.S. health officials reported the first case of what later became known as AIDS in June 1981.

condom stuck in vagina what to do
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How Do You Get HIV?

Most people get HIV through certain sexual behaviors and the use of needles and syringes because these acts expose them to the blood and body fluids of people with HIV.

The virus lives in blood, semen, pre-seminal fluid, rectal and vaginal fluids, and breast milk. You can get HIV when one of these tainted fluids enters your bloodstream or passes through mucous membranes (found in the rectum, vagina, penis, and mouth) or through damaged tissue.

People acquire HIV by having anal or vaginal sex with someone who has HIV who isn't using a condom or isn't taking medicines to treat the virus and prevent transmission.

Another common way people get HIV is by sharing needles, syringes, and other equipment for injecting drugs with someone who has HIV.

Less commonly, babies of mothers with HIV may be born with the infection or acquire it during birth or while breastfeeding. Health care workers who handle HIV-contaminated needles and other sharp objects are at risk of accidental needlesticks that can lead to infection.

People rarely get HIV by having oral sex although, in theory, it is possible, especially if a person has open mouth sores or bleeding gums. Other factors, like genital sores, menstrual blood, and sexually transmitted diseases may affect the risk of transmission during oral sex. Female to female transmission is rare but it can happen.

HIV is not acquired through casual contact. You don't get it from saliva or tears, kissing, mosquito bites, shared toilet seats, or food prepared by someone with HIV. (Open-mouth kissing may be risky if both partners have mouth sores or bleeding gums.) And while HIV used to be passed through donated blood, organs, and tissues, screening procedures in the U.S. have dramatically lowered that risk.


People can avoid getting HIV and lower the chances of infecting other people with the virus by taking advantage of multiple prevention strategies.

The most effective way to prevent the transmission of HIV from person to person is to abstain from anal, vaginal, and oral sex.

Before having sex, know your partner's HIV status or talk to your partner about getting tested for HIV. You and your sex partner also should be tested for other sexually transmitted infections (STIs) and receive treatment if necessary. Having an STI can increase the risk of getting HIV and passing the virus to others.

Using condoms correctly every time you have any kind of sex (vaginal, anal, or oral) is crucial. Condoms provide a barrier that can provide protection from HIV. If you are HIV-positive, using a condom can reduce the risk that you will transmit the virus to others.

If you are HIV-negative, having fewer sex partners can lower your risk of having a partner with HIV or another STI. And, if you are at high risk of acquiring HIV, talk to your doctor about taking daily medicine called pre-exposure prophylaxis to prevent infection.

If you think you've been exposed to HIV, seek immediate medical care. Starting medicines called post-exposure prophylaxis within 72 hours of exposure can help prevent infection.

If you are HIV-positive, you can protect your partner and yourself by taking antiretroviral therapy–medicines that reduce the amount of HIV in your blood and body.

HIV Progression

HIV infection is immediate but the impact on a person's immune system evolves over time. Within a couple of weeks of getting HIV, you may experience flu-like symptoms, like fever and fatigue. During this acute stage, the virus multiplies rapidly and spreads throughout the body.


Eventually, HIV enters a chronic stage. The virus remains active but replicates at a slower rate. You may feel better and have fewer or no symptoms. But the virus will eventually wreck your immune system if you don't seek treatment.

The final stage is full-blown AIDS. This occurs when the number of infection-fighting white blood cells, called CD4 cells, declines, and/or when you develop at least one additional serious infection or disease.

Bacterial, fungal, viral, and parasitic infections, including pneumocystis pneumonia, Kaposi's sarcoma (a type of cancer that causes spots on the skin), and tuberculosis are called opportunistic infections. These infections take advantage of a person's damaged immune system.

Opportunistic infections are less common today than at the height of the AIDS epidemic because new treatments enable people with HIV to live longer, healthier lives. But they can still occur, especially if people don't know they have HIV or don't seek treatment.

This diagram depicts the progression of HIV from acute HIV infection to chronic HIV infection and, finally, to AIDS.

HIV Mouth Sore


Oral health problems are common symptoms of HIV/AIDS. Candidiasis, or a yeast infection, for example, can produce white or yellow cottage cheese-like patches in the mouth or on the tongue. Underneath these patches, the skin is red or bleeding. An oral yeast infection, also called thrush, can sometimes cause a burning sensation, too.

HIV-related Nail Changes


Fingernail and toenail changes can happen to anyone but are more common in people with compromised immune systems. People with HIV and AIDS commonly develop onychomycosis, a fungal infection that causes nails to discolor, thicken, and separate from the nail bed.


One in seven people in the U.S. have HIV but don't know it. The only way to confirm a diagnosis is to get tested.

Most HIV tests (including test kits for home use) detect antibodies that your body produces in response to the virus. "Rapid" antibody screening tests can provide results in 30 minutes or less. These tests use blood or a swab of your mouth. Most people develop antibodies within three to 12 weeks of being infected.

Combination HIV tests use blood to look for antibodies that your body makes as well as antigens–or proteins–that are part of the virus. It takes two to six weeks for someone with HIV to make enough antibodies and antigens for this test to detect the virus. These tests are becoming more common in the U.S.

Nucleic acid tests detect the infection in the blood, but they are expensive and not routinely administered unless someone has had a high-risk exposure to HIV or possible exposure with early HIV symptoms.

No test can immediately detect the virus. There's a window of time between exposure to the virus and when these tests can reliably detect HIV. But you should talk to your doctor immediately if you think you may have been exposed to HIV.

Positive results must be confirmed with further testing before a diagnosis is made. A negative result within three months of exposure should be repeated three months later.


HIV treatment is called antiretroviral therapy (ART), which involves taking a combination of medicines every day. More than 25 medicines are approved by the U.S. Food and Drug Administration (FDA) to treat HIV, and some of these medicines are available as combination pills.

These medicines fall into six drug classes that differ in how they attack the virus. Each class of medicines targets the virus at a different stage of the HIV life cycle.

Antiretroviral Therapy

ART doesn't cure HIV. But it does slow the virus's attack on the immune system, keeping people healthier longer. It also helps reduce the risk of HIV transmission. The U.S. Department of Health and Human Services (HHS) recommends that people diagnosed with HIV start antiretroviral therapy immediately.

The specific medicines in each person's HIV drug regimen vary depending on individual needs, including the amount of virus in a person's blood, other health conditions a patient may have, or whether she is pregnant. Doctors may also consider possible side effects and potential drug interactions as well as the cost and convenience of various options when prescribing ART.

Typically, it takes three to six months for these medicines to reduce the amount of virus in the blood to an undetectable level.



  • Nucleoside reverse transcriptase inhibitors, a class that includes abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir disoproxil fumarate, and zidovudine.
  • Non-nucleoside reverse transcriptase inhibitors. This class includes four drugs: efavirenz, etravirine, nevirapine, and rilpivirine.
  • Protease inhibitors. These are atazanavir, darunavir, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, and tipranavir.
  • Fusion inhibitors. There's only one drug in this class. It's called enfuvirtide.
  • Entry inhibitors, a category that includes one drug: maraviroc.
  • Integrase inhibitors. These are dolutegravir, elvitegravir, and raltegravir.
  • Other medicines. These include cobicistat, a drug used to boost the effectiveness of an HIV medicine, and more than a dozen products that combine two or more HIV medicines from different drug classes.

When To See a Doctor

Even if you don't feel sick, talk to your health care provider if you think you've been exposed to HIV. No test can immediately detect the virus, but your doctor can advise you about when to start testing and what precautions to take. They may also conduct a baseline physical evaluation.

Seek immediate medical attention if you are HIV-negative (or don't know your HIV status) and are exposed to HIV, whether it's through unprotected sex or a condom break; needle or equipment sharing for injecting drugs; sexual assault; or, in health care settings, an accidental needlestick injury. You have 72 hours from the time of exposure to begin taking medicines (called post-exposure prophylaxis) to prevent HIV–and the sooner you start, the better.

If you test positive using a home test kit, see your doctor or find an HIV specialty clinic that can provide follow-up testing and ongoing care. In fact, any positive test requires confirmation.

People who are HIV-positive can expect to have repeated lab tests as part of their routine care and more frequent visits anytime there is a change in symptoms or medications. Ongoing care may also require visits with a range of health care providers–including dentists, counselors, and other medical specialists–to manage the condition.

Is HIV Curable?

There's no cure for HIV, but it's manageable if patients take their medicines as directed. People who are treated before the disease progresses too far can expect to live nearly as long as someone who does not have HIV, according to the CDC.

Antiretroviral drugs introduced in the mid-1990s prolong life by reducing a person's "viral load"–the amount of virus in the blood and body fluids–and boosting their CD4 (white blood cell) counts. That gives the immune system a fighting chance.

Taking these medicines regularly, as directed, can prevent HIV-related opportunistic infections and lower your risk of infecting other people. While HIV remains present in blood and body fluids, the amount of the virus declines, ideally to an undetectable level. That's why it's important to get diagnosed as soon as possible to initiate treatment.

The decades-long search for a vaccine to prevent HIV infection or treat people who are HIV-positive continues. According to HIV.gov, an official website of the HHS, even a vaccine that only protects some people would go a long way toward reducing the number of new HIV infections.


HIV in Children

HIV in children can progress more quickly than in adults, according to the CDC. But, the earlier a child with HIV starts taking antiretroviral treatment, the better off they will be.

Often, these infections occur during childbirth. Treating the mother can prevent the transmission of HIV to her baby. Plus, a short course of HIV medicine for the baby can provide added protection. These children typically receive zidovudine for four to six weeks after birth.

Breast milk also poses a risk if a new mom is HIV-positive. The HHS recommends that HIV-positive women use infant formula instead.

Testing babies for HIV usually begins at 14 to 21 days after birth and continues at one to two months and again at four to six months. Two negative or two positive tests are required to confirm their HIV status.

Thanks to preventive measures, there has been a dramatic reduction in the number of babies born with HIV in the U.S. The estimated number of infants born with perinatal HIV infection (the result of mother-to-child transmission) dropped to 69 in 2013 from 216 in 2002, according to a study published in JAMA Pediatrics in 2017.

However, gaps in diagnosis and treatment remain. During the study period, a majority of moms who gave birth to infants born with HIV were black or Hispanic, and more than a third of the births occurred in just five states (Florida, Texas, Georgia, Louisiana, and Maryland).

Living With HIV

Living with HIV means sticking to a treatment plan. But life can sometimes make that difficult.

Remembering to take your medicines daily, without fail, is just one of the challenges you may face. Some medication regimens are complex, with multiple medicines taken at different times, with or without food. If you're working or traveling, popping pills may prove inconvenient. Setting a schedule, planning ahead, and using pillboxes and other reminders may help.

HIV-related infections can make it difficult for some people to swallow pills. Talk to your health care provider about liquid versions of antiretroviral medicines or whether the pills you take can be split or crushed.

Maintaining a healthy diet is key to supporting your immune system. But that can be hard to do when you're struggling with HIV-related metabolism changes or medication side effects, such as nausea or diarrhea. You may find it helpful to consult with a nutritionist to navigate these issues.

People with HIV may also experience mental health issues, such as depression, anxiety, and suicidal thoughts. Your doctor can help you find a qualified mental health professional. You may also benefit from finding a case manager who can help with the day-to-day challenges of living life with HIV, including housing, transportation, and childcare.

Vial of blood after blood test
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HIV and Pregnancy

Pregnant or planning a pregnancy? If so, you should be tested for HIV as soon as possible. Women who are HIV-positive and pregnant not only have to take care of their own health, they need to preserve the health of their unborn babies.

Most antiretroviral medicines are safe for use during pregnancy. These medicines lower the amount of virus in the woman's body, keeping her healthy and reducing the risk of transmitting the virus to her fetus.

If a woman is already taking HIV medicines, typically her doctor will keep her on those medicines. Any woman who learns she is HIV-positive during pregnancy should start an antiretroviral regimen as soon as possible.

A woman's risk of transmitting the infection is greatest during childbirth when the newborn is exposed to her blood and other body fluids. If the amount of virus in the woman's body is high or unknown near the time of delivery, doctors typically order an IV of zidovudine, which passes across the placenta from a mom to her unborn baby. This drug prevents the mother-to-be from transmitting HIV to the baby during delivery.

A scheduled cesarean section may be another option for reducing the risk of transmission.

Celebrities With HIV

HIV doesn't care if you're famous or not. Actors, athletes, and entertainers are just as vulnerable as other people who are exposed to the virus.

Los Angeles Lakers point guard Magic Johnson stunned the world with his 1991 retirement from basketball after learning he had HIV. He created the Magic Johnson Foundation to fight HIV and, decades later, remains an advocate for HIV and AIDS prevention.

Olympic diver Greg Louganis, diagnosed in 1988, has gone through many treatments throughout the years. As he told ESPN The Magazine in 2016, "HIV has taught me that I'm a lot stronger than I ever believed I was."

Charlie Sheen publicly revealed his HIV status in 2015. In 2016, the Golden Globe-winning actor joined a clinical trial of an injectable drug called PRO 140. The experimental medication belongs to a new class of medications called entry inhibitors designed to protect healthy cells from HIV infection. Sheen reportedly credits the antiviral therapy with a positive transformation of his health, even though it is not yet FDA-approved.

Unfortunately, advances in HIV and AIDS research came too late for many celebrities, including tennis great Arthur Ashe, who believed he contracted the virus via a blood transfusion and became an advocate for public awareness of the disease.

Others who have died from HIV and AIDS include Queen's lead vocalist and songwriter Freddie Mercury; heartthrob actor Rock Hudson; Anthony Perkins, who played Norman Bates in the psychological thriller Psycho; TV dad Robert Reed of The Brady Bunch; and Tom Fogerty, lead singer of the rock band Creedence Clearwater Revival.

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