Resource Library


Answers to common questions about HIV and AIDS, including transmission, risks and facts about treatment.

Información Sobre VIH/SIDA [Spanish]

It’s understandable to have a lot of questions about HIV and AIDS. No question to too basic: Trust us, we’ve been answering all sorts of questions about HIV and AIDS since 1982.

Some of the most common questions appear below in a few sections.


HIV stands for Human Immunodeficiency Virus. It’s the virus that can cause AIDS. HIV infects humans and causes damage by taking over cells in the immune system–the part of the body that usually works to fight off germs, bacteria and disease.

What is AIDS?

AIDS stands for Acquired Immune Deficiency Syndrome. AIDS is a group of symptoms that can eventually result from an HIV infection if it’s not treated. AIDS is often considered an advanced stage of HIV infection, causing damage to the body’s immune system and ongoing inflammation. When that happens, the body may not be able to fight off certain types of illnesses or cancers. When the body’s immune system is damaged to a certain level because of HIV, this can mean a person is diagnosed with AIDS.

How does HIV become AIDS?

AIDS begins with HIV infection. People who have HIV may have no symptoms for 10 years or longer (though they can still transmit HIV to others). If the infection is not detected and treated, the immune system gradually weakens and AIDS develops. But, if the infection is identified, today’s extremely effective treatments can lower the amount of HIV in the body to undetectable levels, resulting in much better health (and the virus won’t be transmitted to others).


HIV and AIDS are terms that are often used together, and sometimes are used interchangeably, though they are not the same thing.

HIV stands for Human Immunodeficiency Virus.

AIDS stands for Acquired Immune Deficiency Syndrome.

Often, the difference isn’t clear because many people write “HIV/AIDS,” but remember, HIV and AIDS aren’t the same.


HIV is a virus. AIDS is a condition caused by HIV.

You can have HIV without developing AIDS and many people live for many years with HIV without ever developing AIDS. But if you have AIDS, you have to have HIV.

The National Institutes of Health (NIH) have more detailed information about the medical diagnosis of AIDS, which consists of having HIV plus having a very low count of CD4 cells and/or an opportunistic infection. CD4 cells are part of the immune system and are attacked/destroyed by HIV.


If you think you may have been infected with HIV, find a place to get a free, confidential HIV test. If you are worried about a recent potential exposure, go to the emergency room and ask for PEP (post-exposure prophylaxis) as soon as you can. PEP can prevent HIV infection in someone who has been recently exposed to HIV if it’s started within 72 hours (three days) of the possible infection.  Effectiveness is increased the earlier PEP is begun after the exposure.

You can have HIV and not have any symptoms, and some HIV tests will not show a positive result for as long as three months after infection. This is referred to as the HIV test window period and has to do with how HIV tests detect the virus.

Some people recently infected with HIV will experience some “flu-like” symptoms. These might include:

  • Fever
  • Severe fatigue
  • A non-itchy rash
  • Swollen glands/lymph nodes
  • Muscle aches
  • Sore throat
  • Night sweats
  • Sores or ulcers in your mouth

Acute HIV Infection Stage

This is called “acute retroviral syndrome” (ARS) or “primary HIV infection” and can last from a few days to a few weeks. You could get sick enough to go to the emergency room or just feel a little unwell. It’s important to remember that people experience similar symptoms and it’s not related to HIV. Sometimes, the flu is just the flu.

Clinical Latency Stage

After the acute phase, the virus typically becomes less active in the body for as long as 10 years, during which you might have no symptoms at all. An HIV test will detect the virus during this period. This is one of the reasons that it’s important for sexually-active people to routinely get tested. The signs of HIV infection are easy to miss or misinterpret.


There is not one set of symptoms that defines AIDS. When immune system damage is severe, people experience opportunistic infections. The term “opportunistic” refers to infections caused by things which our immune systems can usually defend against.

Some examples are shingles, Kaposi’s sarcoma, non-Hodgkin’s lymphoma, thrush, tuberculosis, and candida esophagitis. The National Institutes of Health (NIH) has a more detailed list of illnesses that are common as AIDS progresses.

In the past, having AIDS was defined as having HIV infection and getting one of these other diseases. Today, a person may also be diagnosed with AIDS if they are living with HIV and have a CD4 cell (a type of immune system cell) count below 200 cells per cubic millimeter, even without an opportunistic infection.

The NIH website is a good resource for a more detailed listing and description of medical diagnosis of AIDS.

There’s a medicine that HIV-negative people can take that prevents HIV infection. It’s called PrEP, or Pre-Exposure Prophylaxis. Not only is it extremely effective, but there are also payment assistance programs to help you pay for it.

Transmission & Risk

You cannot get HIV from kissing. Oral sex is a lower risk activity, and if you get semen in your eye, the chance you’re going to become infected with HIV is quite low. What else do you want to know? Read on!


How do you get infected with HIV? How is HIV transmitted? How do you catch HIV? How do you get AIDS?

You can’t “catch” AIDS; you only develop AIDS if you have contracted HIV.

HIV can only be transmitted from a person living with HIV who has a detectable viral load to another person through direct contact of the following bodily fluids:

  • Blood (including menstrual blood)
  • Semen / cum / precum / ejaculate
  • Vaginal secretions
  • Breast milk

HIV may pass from one person to another any time there is contact with semen, pre-cum, vaginal fluids or blood. HIV is oftentimes transmitted during sex and when using injection drugs and sharing needles. Mothers can also transmit HIV to their babies before or during birth or while breastfeeding, although this is very rare in the U.S. and in other places where mothers living with HIV have access to health care services.

People living with HIV who are taking HIV medications and have a suppressed viral load (who are “undetectable”) do not transmit HIV. People who are HIV-negative can prevent HIV infection with by using PrEP (pre-exposure prophylaxis).


NO. HIV is not transmitted by kissing.


Oral sex is “low risk” in terms of HIV transmission. That means, you probably will not get HIV from giving or receiving oral sex. Having cuts or sores in your mouth, gum disease, having a sexually-transmitted infection (STI) in your throat, or recent dental work increases your risk.

Although the chance of getting infected with HIV from oral sex is very low, you can get other STIs such as gonorrhea and chlamydia if you give or receive oral sex.

You can prevent STI infection during oral sex by using a condom or dental dam. You can prevent further transmission of STIs by regularly getting tested and treated for STIs.


It’s easier to get HIV from some types of sex than others.


  1. Oral sex is a great way to minimize your exposure to HIV.
  2. Oral, anal and vaginal sex with a condom can prevent HIV transmission.
  3. For men who have sex with men, topping without a condom is less likely to transmit HIV than bottoming without a condom.
  4. People living with HIV who take their medications and remain virally suppressed (are undetectable) do not transmit HIV to other people.
  5. People who are HIV-negative can take PrEP to prevent HIV infection.

Can an HIV-negative person have sex with a person who is living with HIV and stay HIV-negative? Yes. Many people prevent HIV infection with PrEP, using condoms and lube, or by ensuring that the partner living with HIV is on HIV medications and remains virally suppressed.

The most common means of becoming HIV positive for men who have sex with men is bottoming without a condom.

Consider PrEP if you are worried about HIV transmission and/or do not always use condoms.

If you think you may have come into contact with HIV, get a free, confidential HIV test at one of our sites in San Francisco.

Testing for HIV

If you’re having sex or injecting drugs, we recommend you get tested for HIV and STIs every three months. Testing is no big deal, and it’s the only way to know your status. If you test positive for HIV, there are really effective treatments that can help you stay healthy and live a long time.


If you think you have been exposed to HIV, find a place to get a free, confidential HIV test right away. It may be appropriate for you to start medication immediately. This what’s called post-exposure prophylaxis, or PEP (Learn more about PEP). Starting PEP within 72 hours of an HIV exposure can prevent you from becoming HIV-positive (also known as seroconverting). Starting PEP as soon as possible after exposure is best. A trained test counselor will help assess your risk and recommend whether or not PEP is right for you.

The time it takes for a person who has been infected with HIV to show a positive test result is called the “window period.” There are different types of HIV tests, and each type has a different window period. Ask your local HIV organization or medical provider what type of test they are offering. They will be able to give you more information about how long it might take for a person with HIV to test positive with the test they are using.

If you think you have been exposed to HIV, get tested and talk to your HIV counselor about testing and PEP. You can also access HIV testing and PEP at most hospital emergency departments.

What does this mean for you?

Any time that you have reason to think you’ve been directly exposed to HIV, you should consult with your doctor or a trained HIV test counselor as soon as possible. The sooner you address the possibility, the better for you and your future sexual partners.

  • If you test negative on an HIV RNA test after two weeks of possibly being exposed, you are very likely HIV-negative.
  • If you test negative on a fourth generation HIV test or lab assay that detects HIV antigens (part of the HIV virus) in addition to antibodies after three or four weeks after possibly being infected, you are very likely HIV-negative.
  • If you test negative on an antibody test taken three months or longer after your last possible risk of possible exposure to HIV, you are likely HIV-negative.

The person who gives you your HIV test will have additional information about the window period.

For this reason, we recommend that people who are having sex get tested every three months. Routine testing is painless and ensures that if you do get infected, you can start treatment right away.


Do you think you may have been exposed to HIV? Find a test location – a trained counselor will help you get tested and make a plan.

There’s a period of time after a person is infected during which they won’t test positive. This is called the HIV “window period.”

The window period can be from 10 days to three months, depending on the person’s body and on the type of HIV test that’s used. During that time, you can test HIV-negative even though you’re HIV-positive. You can still get HIV from someone who is in the window period.

If you’ve had high-risk exposure to HIV within the last few days, you should ask your test counselor about PEP (post-exposure prophylaxis).


The HIV test window period varies depending on what kind of HIV test you take. We recommend getting tested every three months if you’re having sex.

Rapid HIV antibody tests give a positive result based on antibodies your body makes to respond to HIV. Rapid HIV antibody tests do not test the virus itself. It takes your body up to three months to produce HIV antibodies at levels that can be detected by this test.

  • Four to six weeks (up to three months) after infection, most people will have enough antibodies to test positive.
  • 12 weeks (three months) after infection, about 98 percent of people will have enough antibodies to test positive.

Rapid antibody/antigen combination tests detect antibodies to HIV in addition to fragments of the virus called the p24 antigen. The p24 antigen can be detected in the body earlier than antibodies. According to the manufacturer:

  • 12 to 26 days after infection, the p24 antigen can be detected by this type of test
  • 20 to 45 days after infection, HIV antibodies can be detected by this type of test

HIV RNA tests show a positive result based on the presence of the virus. These tests are more expensive than antibody tests, so are not offered in as many places.

  • 10 to 14 days after infection there will be enough viral material for a positive result.

Home testing kits – As of Fall 2012, there are two “home tests” which have been approved by the FDA for use in the U.S.:

  • OraQuick by OraSure is an antibody test that you complete at home, usually conducted using oral fluid. According to the manufacturer, the window period is three months. Up to one in 12 people may receive a false-negative result (i.e., the test says they’re negative, but they’re actually HIV-positive) with this test.
  • Home Access HIV-1 by Home Access Health Corp is not actually a test, but a sample-collection kit. You use it to collect a blood sample which you then mail to a lab for processing. This test is anonymous.

PCR tests (polymerase chain reaction tests) also test for the actual virus. This type of HIV test is often used for testing the viral load of HIV-positive people, as well as testing babies born to HIV-positive mothers. You can read more about PCR tests on the website.

  • Two to three weeks after infection, there will be enough viral material for a positive result.

Anonymous and confidential HIV tests use the same testing method. The only difference is that one does not have your name attached to the results.

HIV antibody testing is available at anonymous HIV test sites in some California counties. Anonymous testing means that absolutely no one other than you has access to your test results since your name is not recorded at the test site. It is always a good idea to contact the testing clinic directly to confirm what type of test is available.

HIV antibody testing means that you and the health care provider know your results, and it may be recorded in your medical file at the testing site. Some clinics offer confidential testing to make it easier for you to access your own results at a later date, or to make it easier to track the number of unique new cases that are being found.

As a condition of funding, some local governments require confidential testing rather than anonymous testing. This makes it easier for agencies to distinguish new HIV infections from cases of someone testing positive in multiple locations.

Even if the testing facility does not offer anonymous testing, your test results are protected by HIPAA regulations, which require health facilities to tightly protect your medical records so that only you and authorized people may see them.

Learn more about HIV Testing.


A positive HIV test result means that:

  • Depending on the type of HIV test, either HIV virus or antibodies to the virus were detected in your blood.
  • You are “HIV-positive.”
  • It is possible to infect other people with HIV, unless further viral load testing indicates that you are “undetectable.”

(Note that certain tests are not conclusive; your HIV test counselor will let you know if a re-test is appropriate).

A negative HIV test result means that:

  • No indication of HIV or antibodies specific to HIV was found by the test.

A negative HIV test result does NOT mean:

  • It does not absolutely mean you are not infected with HIV (you might still be in the window period)
  • It does not mean you are immune to HIV
  • It does not mean you have a resistance to HIV infection
  • It does not mean you will never get HIV

If you are having sex, we recommend getting tested every three months.


Presently, there is no cure for HIV or AIDS. There is no readily available procedure or medication which has been scientifically proven to reliably eliminate the virus from a person’s body or reverse the damage to the immune system.

There have been many advances in HIV treatments and therapies in recent years that have dramatically improved the quality of life for people with HIV. People are living longer and healthier with HIV than we used to think was possible.

There are also people whose bodies naturally suppress the virus without medication (referred to as “elite controllers”), though this happens rarely. Even some elite controllers opt to take antiretrovirals to reduce the damage caused by HIV to their immune system.

As of March 2019, two people been “functionally cured” of HIV. Both of these people were being treated for cancer and underwent intense therapy and a stem cell bone marrow transplant using HIV-immune cells. This is a very intensive, high-risk procedure.

“Functionally cured” means that the person doesn’t have to take medications and there’s so little of the virus in their body that they aren’t being affected by it and can’t infect anyone else. It’s not 100 percent clear whether or not this will remain true in the long term.

  • The first well-studied case of a person who was ‘functionally cured’ of HIV is Timothy Brown, also known as “the Berlin Patient.”
  • In 2019, it was announced that a second person, “the London Patient” has also been “functionally cured” of HIV.

Read about the science behind the these cases on the section of our blog called BETA.

There are also cases of HIV-infected infants born to HIV-positive mothers that were given antiretroviral medications soon after birth that had been thought to be functionally cured of HIV.

  • The “Mississippi Baby” maintained an undetectable viral load off of antiretrovirals for more than two years, but eventually the virus did return and began replicating.
  • A young French woman infected during birth and given early treatment is described as being in “remission” since she has maintained an undetectable viral load for 12 years off treatment.
  • Other French adults, known as the VISCONTI cohort, who received early HIV treatment have maintained undetectable viral loads even without antiretroviral therapy.

It is not clear if these “post-treatment controllers” will suppress HIV replication in the long-term or if the virus will return as it did in the case of the Mississippi Baby.

Want to know more about progress towards a cure for HIV? BETA has a number of other articles about the latest in HIV cure research.

HIV Treatment & Undetectable

Today’s HIV treatments, called antiretroviral therapy or ART, are extremely effective. Some treatments are a single tablet. Long-acting injectable medications are likely to be approved and available soon. Medicine has come a long way since the first HIV treatment options became available in the 1990s.

There is still no functional cure for HIV, but ART can help people live long, healthy lives. Today’s medications are provided in combinations that reduce a person’s viral load to levels so low it’s undetectable. People who become undetectable cannot transmit the virus to others.


“Viral load” is a term that describes how much virus a person living with HIV has in their body.

Without HIV medications, the virus replicates (makes copies of itself) which causes the amount of virus in the body to increase.

HIV medications prevent HIV from making copies of itself. Then, the amount of HIV in the body goes down.

To see how well HIV treatments are working, doctors and other providers measure the amount of virus in the blood and report a measurement called your “viral load.” It’s simply a measurement of how many copies of the virus are in a single unit (a milliliter) of blood.

A very low amount of virus may even be “undetectable” by viral load tests (this is a good thing, and often the goal of treatment). A common “undetectable” level is <20 copies per milliliter of blood. “Low” viral loads are those that are less than 200 copies per milliliter. Very high viral loads can be over 500,000 copies per milliliter.


The goal of antiretrovirals is to suppress the ability of the virus to replicate, lowering the presence of virus in your body to “undetectable” levels.

Being undetectable means there are so few copies of the virus in your body that it can’t be measured by standard viral load tests. If you are undetectable, you will still test positive on common HIV antibody tests because they do not measure viral load, but rather antibodies to the virus that persist despite changes in the level of virus in the bloodstream.

Studies have demonstrated that being undetectable (<200 copies/mL) for at least six months means you won’t transmit HIV to others through sex. Read more about undetectable.

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