HIV stands for human immunodeficiency virus. It weakens a person’s immune system by destroying important cells that fight disease and infection. No effective cure exists for HIV, but with proper medical care, HIV can be controlled.
This article will give you basic information about HIV, such as how it’s transmitted, how you can prevent it, and how to get tested for HIV.
Some groups of people in the United States are more likely to get HIV than others because of many factors, including their sex partners, their risk behaviors, and where they live.
What is HIV?
HIV stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome or AIDS if not treated. Unlike some other viruses, the human body can’t get rid of HIV completely, even with treatment. So once you get HIV, you have it for life.
HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. Untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get other infections or infection-related cancers.
Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection.
No effective cure currently exists, but with proper medical care, HIV can be controlled. The medicine used to treat HIV is called antiretroviral therapy or ART.
If taken the right way, every day, this medicine can dramatically prolong the lives of many people infected with HIV, keep them healthy, and greatly lower their chance of infecting others.
Before the introduction of antiretroviral therapy in the mid-1990s, people with HIV could progress to AIDS in just a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.
Where did HIV come from?
Scientists identified a type of chimpanzee in Central Africa as the source of HIV infection in humans. They believe that the chimpanzee version of the immunodeficiency virus (called simian immunodeficiency virus, or SIV) most likely was transmitted to humans and mutated into HIV when humans hunted these chimpanzees for meat and came into contact with their infected blood.
Studies show that HIV may have jumped from apes to humans as far back as the late 1800s. Over decades, the virus slowly spread across Africa and later into other parts of the world.
We know that the virus has existed in the United States since at least the mid to late 1970s.
What are the stages of HIV?
When people get HIV and don’t receive treatment, they will typically progress through three stages of disease.
Stage 1: Acute HIV infection
Within 2 to 4 weeks after infection with HIV, people may experience a flu-like illness, which may last for a few weeks. This is the body’s natural response to infection. When people have acute HIV infection, they have a large amount of virus in their blood and are very contagious.
But people with acute infection are often unaware that they’re infected because they may not feel sick right away or at all. To know whether someone has acute infection, either a fourth-generation antibody/antigen test or a nucleic acid (NAT) test is necessary.
If you think you have been exposed to HIV through sex or drug use and you have flu-like symptoms, seek medical care and ask for a test to diagnose acute infection.
Stage 2: Clinical latency (HIV inactivity or dormancy)
This period is sometimes called asymptomatic HIV infection or chronic HIV infection. During this phase, HIV is still active but reproduces at very low levels. People may not have any symptoms or get sick during this time.
For people who aren’t taking medicine to treat HIV, this period can last a decade or longer, but some may progress through this phase faster. People who are taking medicine to treat HIV (ART) the right way, every day may be in this stage for several decades.
It’s important to remember that people can still transmit HIV to others during this phase, although people who are on ART and stay virally suppressed (having a very low level of virus in their blood) are much less likely to transmit HIV than those who are not virally suppressed.
At the end of this phase, a person’s viral load starts to go up and the CD4 cell count begins to go down. As this happens, the person may begin to have symptoms as the virus levels increase in the body, and the person moves into Stage 3.
Stage 3: Acquired immunodeficiency syndrome (AIDS)
AIDS is the most severe phase of HIV infection. People with AIDS have such badly damaged immune systems that they get an increasing number of severe illnesses, called opportunistic illnesses.
Without treatment, people with AIDS typically survive about 3 years.
Common symptoms of AIDS include chills, fever, sweats, swollen lymph glands, weakness, and weight loss.
People are diagnosed with AIDS when their CD4 cell count drops below 200 cells/mm or if they develop certain opportunistic illnesses. People with AIDS can have a high viral load and be very infectious.
How are people exposed to HIV?
First, let’s talk about the ways you CANNOT get HIV.
HIV does not survive long outside the human body (such as on surfaces), and it cannot reproduce outside a human host. It is not spread by
- Mosquitoes, ticks, or other insects.
- Saliva, tears, or sweat that is not mixed with the blood of an HIV-positive person. There is no risk of getting HIV from spitting or scratching because no body fluids are transferred between people.
- Hugging, shaking hands, sharing toilets, sharing dishes, or closed-mouth or “social” kissing with someone who is HIV-positive.
- Other sexual activities that don’t involve the exchange of body fluids (for example, touching).
Can I get HIV from anal sex?
Yes. In fact, anal sex is the riskiest type of sex for getting or transmitting HIV.
HIV can be found in certain body fluids—blood, semen (cum), pre-seminal fluid (pre-cum), or rectal fluids—of a person who has HIV. Although receptive anal sex (bottoming) is much riskier for getting HIV than insertive anal sex (topping), it’s possible for either partner—the top or the bottom—to get HIV.
The bottom’s risk is very high because the lining of the rectum is thin and may allow HIV to enter the body during anal sex. The top is also at risk because HIV can enter the body through the opening at the tip of the penis (or urethra); the foreskin if the penis isn’t circumcised; or small cuts, scratches, or open sores anywhere on the penis.
Can I get HIV from vaginal sex?
Yes. Either partner can get HIV through vaginal sex, though it is less risky for getting HIV than receptive anal sex.
When a woman has vaginal sex with a partner who’s HIV-positive, HIV can enter her body through the mucous membranes that line the vagina and cervix. Most women who get HIV get it from vaginal sex.
Men can also get HIV from having vaginal sex with a woman who’s HIV-positive. This is because vaginal fluid and blood can carry HIV. Men get HIV through the opening at the tip of the penis (or urethra); the foreskin if they’re not circumcised; or small cuts, scratches, or open sores anywhere on the penis.
Can I get HIV from oral sex?
The chance that an HIV-negative person will get HIV from oral sex with an HIV-positive partner is extremely low.
Oral sex involves putting the mouth on the penis (fellatio), vagina (cunnilingus), or anus (anilingus). In general, there’s little to no risk of getting or transmitting HIV through oral sex.
Factors that may increase the risk of transmitting HIV through oral sex are ejaculation in the mouth with oral ulcers, bleeding gums, genital sores, and the presence of other sexually transmitted diseases (STDs), which may or may not be visible.
You can get other STDs from oral sex. And, if you get feces in your mouth during anilingus, you can get hepatitis A and B, parasites like Giardia, and bacteria like Shigella, Salmonella, Campylobacter, and E. coli.
Is there a connection between HIV and other sexually transmitted infections?
Yes. Having another sexually transmitted disease (STD) can increase the risk of getting or transmitting HIV.
If you have another STD, you’re more likely to get or transmit HIV to others. Some of the most common STDs include gonorrhea, chlamydia, syphilis, trichomoniasis, human papillomavirus (HPV), genital herpes, and hepatitis.
The only way to know for sure if you have an STD is to get tested. If you’re sexually active, you and your partners should get tested for STDs (including HIV if you’re HIV-negative) regularly, even if you don’t have symptoms.
If you are HIV-negative but have an STD, you are about 3 times as likely to get HIV if you have unprotected sex with someone who has HIV. There are two ways that having an STD can increase the likelihood of getting HIV.
If the STD causes irritation of the skin (for example, from syphilis, herpes, or human papillomavirus), breaks or sores may make it easier for HIV to enter the body during sexual contact.
Even STDs that cause no breaks or open sores (for example, chlamydia, gonorrhea, trichomoniasis) can increase your risk by causing inflammation that increases the number of cells that can serve as targets for HIV.
If you are HIV-positive and also infected with another STD, you are about 3 times as likely as other HIV-infected people to spread HIV through sexual contact.
This appears to happen because there is an increased concentration of HIV in the semen and genital fluids of HIV-positive people who also are infected with another STD.
Does my HIV infected partner’s viral load affect my risk of getting HIV?
Yes, as an HIV-positive person’s viral load goes down, the chance of transmitting HIV goes down.
Viral load is the amount of HIV in the blood of someone who is HIV-positive. When the viral load is very low, it is called viral suppression. Undetectable viral load is when the amount of HIV in the blood is so low that it can’t be measured.
In general, the higher someone’s viral load, the more likely that person is to transmit HIV. People who have HIV but are in care, taking HIV medicines, and have a very low or undetectable viral load are much less likely to transmit HIV than people who have HIV and do not have a low viral load.
However, a person with HIV can still potentially transmit HIV to a partner even if they have an undetectable viral load, because:
- HIV may still be found in genital fluids (semen, vaginal fluids). The viral load test only measures virus in blood.
- A person’s viral load may go up between tests. When this happens, they may be more likely to transmit HIV to partners.
- Sexually transmitted diseases increase viral load in genital fluids.
If you’re HIV-positive, getting into care and taking HIV medicines (called antiretroviral therapy or ART) the right way, every day will give you the greatest chance to get and stay virally suppressed, live a longer, healthier life, and reduce the chance of transmitting HIV to your partners.
If you’re HIV-negative and have an HIV-positive partner, encourage your partner to get into care and take HIV treatment medicines.
Taking other actions, like using a condom the right way every time you have sex or taking daily medicine to prevent HIV (called pre-exposure prophylaxis or PrEP) if you’re HIV-negative, can lower your chances of transmitting or getting HIV even more.
Can I get HIV from injecting drugs?
Yes. Your risk for getting HIV is very high if you use needles or works (such as cookers, cotton, or water) after someone with HIV has used them.
People who inject drugs, hormones, steroids, or silicone can get HIV by sharing needles or syringes and other injection equipment. The needles and equipment may have someone else’s blood in them, and blood can transmit HIV.
Likewise, you’re at risk for getting hepatitis B and C if you share needles and works because these infections are also transmitted through blood.
Another reason people who inject drugs can get HIV (and other sexually transmitted diseases) is that when people are high, they’re more likely to have risky sex.
Stopping injection and other drug use can lower your chances of getting HIV a lot.
You may need help to stop or cut down using drugs, but many resources are available. To find a substance abuse treatment center near you, check out the locator tools on SAMHSA.gov or AIDS.gov, or call 1-800-662-HELP (4357).
If you keep injecting drugs, you can lower your risk for getting HIV by using only new, sterile needles and works each time you inject. Never share needles or works with anyone else.
Can I get HIV from using other kinds of drugs?
When you’re drunk or high, you’re more likely to make decisions that put you at risk for HIV, such as having sex without a condom.
Drinking alcohol, particularly binge drinking, and using “club drugs” like Ecstasy, ketamine, GHB, and poppers can alter your judgment, lower your inhibitions, and impair your decisions about sex or other drug use.
You may be more likely to have unplanned and unprotected sex, have a harder time using a condom the right way every time you have sex, have more sexual partners, or use other drugs, including injection drugs or meth.
Those behaviors can increase your risk of exposure to HIV. If you have HIV, they can also increase your risk of spreading HIV to others. Being drunk or high affects your ability to make safe choices.
If you’re going to a party or another place where you know you’ll be drinking or using drugs, you can bring a condom so that you can reduce your risk if you have vaginal or anal sex.
If I already have HIV, can I get a different kind of HIV?
Yes. This is called HIV superinfection.
HIV superinfection is when a person with HIV gets infected with another strain of the virus. The new strain of HIV can replace the original strain or remain along with the original strain.
The effects of superinfection differ from person to person. Superinfection may cause some people to get sicker faster because they become infected with a new strain of the virus that is resistant to the medicine (antiretroviral therapy or ART) they’re taking to treat their original infection.
Research suggests that a hard-to-treat superinfection is rare. Taking medicine to treat HIV (ART) may reduce someone’s chance of getting a superinfection.
Are health care workers at risk of getting HIV on the job?
The risk of health care workers being exposed to HIV on the job (occupational exposure) is very low, especially if they use protective practices and personal protective equipment to prevent HIV and other blood-borne infections.
For health care workers on the job, the main risk of HIV transmission is from being stuck with an HIV-contaminated needle or other sharp object. However, even this risk is small.
Scientists estimate that the risk of HIV infection from being stuck with a needle used on an HIV-infected person is less than 1%.
Can I get HIV from receiving medical care?
Although HIV transmission is possible in health care settings, it is extremely rare.
Careful practice of infection control, including universal precautions (using protective practices and personal protective equipment to prevent HIV and other blood-borne infections), protects patients as well as health care providers from possible HIV transmission in medical and dental offices and hospitals.
The risk of getting HIV from receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
It is important to know that you cannot get HIV from donating blood. Blood collection procedures are highly regulated and safe.
Can I get HIV from a tattoo or body piercing?
There are no known cases in the United States of anyone getting HIV this way. However, it is possible to get HIV from a reused or not properly sterilized tattoo or piercing needle or other equipment, or from contaminated ink.
It’s possible to get HIV from tattooing or body piercing if the equipment used for these procedures has someone else’s blood in it or if the ink is shared.
The risk of getting HIV this way is very low, but the risk increases when the person doing the procedure is unlicensed, because of the potential for unsanitary practices such as sharing needles or ink.
If you get a tattoo or a body piercing, be sure that the person doing the procedure is properly licensed and that they use only new or sterilized needles, ink, and other supplies.
Can I get HIV from food?
You can’t get HIV from consuming food handled by an HIV-infected person. Even if the food contained small amounts of HIV-infected blood or semen, exposure to the air, heat from cooking, and stomach acid would destroy the virus.
Though it is very rare, HIV can be spread by eating food that has been pre-chewed by an HIV-infected person. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing. The only known cases are among infants.
Can women who have sex with other women contract HIV?
Case reports of female-to-female transmission of HIV are rare. The well-documented risk of female-to-male transmission shows that vaginal fluids and menstrual blood may contain the virus and that exposure to these fluids through mucous membranes (in the vagina or mouth) could potentially lead to HIV infection.
Is the risk of HIV infection different for different people?
Some groups of people in the United States are more likely to get HIV than others because of many factors, including the status of their sex partners, their risk behaviors, and where they live.
When you live in a community where many people have HIV infection, the chances of having sex or sharing needles or other injection equipment with someone who has HIV are higher. You can use CDC’s HIV, STD, hepatitis, and tuberculosis atlas to see the percentage of people with HIV (“prevalence”) in different US communities. Within any community, the prevalence of HIV can vary among different populations.
Gay and bisexual men have the largest number of new diagnoses in the United States. Blacks/African Americans and Hispanics/Latinos are disproportionately affected by HIV compared to other racial and ethnic groups. Also, transgender women who have sex with men are among the groups at highest risk for HIV infection, and injection drug users remain at significant risk for getting HIV.
Risky behaviors, like having anal or vaginal sex without using a condom or taking medicines to prevent or treat HIV, and sharing needles or syringes play a big role in HIV transmission.
Anal sex is the highest-risk sexual behavior. If you don’t have HIV, being a receptive partner (or bottom) for anal sex is the highest-risk sexual activity for getting HIV. If you do have HIV, being the insertive partner (or top) for anal sex is the highest-risk sexual activity for transmitting HIV.
But there are more tools available today to prevent HIV than ever before. Choosing less risky sexual behaviors, taking medicines to prevent and treat HIV, and using condoms with lubricants are all highly effective ways to reduce the risk of getting or transmitting HIV.
How do I know if I have HIV?
The only way to know for sure whether you have HIV is to get tested. Knowing your status is important because it helps you make healthy decisions to prevent getting or transmitting HIV.
Some people may experience a flu-like illness within 2 to 4 weeks after infection (Stage 1 HIV infection). But some people may not feel sick during this stage.
Flu-like symptoms include fever, chills, rash, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes, or mouth ulcers. These symptoms can last anywhere from a few days to several weeks.
During this time, HIV infection may not show up on an HIV test, but people who have it are highly infectious and can spread the infection to others.
If you have these symptoms, that doesn’t mean you have HIV. Each of these symptoms can be caused by other illnesses. But if you have these symptoms after a potential exposure to HIV, see a health care provider and tell them about your risk. The only way to determine whether you are infected is to be tested for HIV infection.
To find places near you that offer confidential HIV testing, visit gettested.cdc.gov. You can also use a home testing kit, available for purchase in most pharmacies and online.
After you get tested, it’s important to find out the result of your test so you can talk to your health care provider about treatment options if you’re HIV-positive or learn ways to prevent getting HIV if you’re HIV-negative.
Is there a cure for HIV?
No effective cure currently exists for HIV, but with proper medical care, HIV can be controlled.
Treatment for HIV is called antiretroviral therapy or ART. If taken the right way, every day, ART can dramatically prolong the lives of many people infected with HIV, keep them healthy, and greatly lower their chance of infecting others.
Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS (the last stage of HIV infection) in a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.