What is HIV?
HIV is a virus that damages the immune system. Untreated HIV affects and kills CD4 cells, which are a type of immune cell called T cell.
Over time, as HIV kills more CD4 cells, the body is more likely to get various types of conditions and cancers.
HIV is transmitted through bodily fluids that include:
- vaginal and rectal fluids
- breast milk
The virus isn’t transferred in air or water, or through casual contact.
Because HIV inserts itself into the DNA of cells, it’s a lifelong condition and currently there’s no drug that eliminates HIV from the body, although many scientists are working to find one.
However, with medical care, including treatment called antiretroviral therapy, it’s possible to manage HIV and live with the virus for many years.
Without treatment, a person with HIV is likely to develop a serious condition called the Acquired Immunodeficiency Syndrome, known as AIDS.
At that point, the immune system is too weak to successfully respond against other diseases, infections, and conditions.
Untreated, life expectancy with end stage AIDS is about 3 yearsTrusted Source. With antiretroviral therapy, HIV can be well-managed, and life expectancy can be nearly the same as someone who has not contracted HIV.
It’s estimated that 1.2 million Americans are currently living with HIV. Of those people, 1 in 7 don’t know they have the virus.
HIV can cause changes throughout the body.
What is AIDS?
AIDS is a disease that can develop in people with HIV. It’s the most advanced stage of HIV. But just because a person has HIV doesn’t mean AIDS will develop.
HIV kills CD4 cells. Healthy adults generally have a CD4 count of 500 to 1,600 per cubic millimeter. A person with HIV whose CD4 count falls below 200 per cubic millimeter will be diagnosed with AIDS.
A person can also be diagnosed with AIDS if they have HIV and develop an opportunistic infection or cancer that’s rare in people who don’t have HIV.
An opportunistic infection such as Pneumocystis jiroveci pneumonia is one that only occurs in a severely immunocompromised person, such as someone with advanced HIV infection (AIDS).
Untreated, HIV can progress to AIDS within a decade. There’s currently no cure for AIDS, and without treatment, life expectancy after diagnosis is about 3 yearsTrusted Source.
This may be shorter if the person develops a severe opportunistic illness. However, treatment with antiretroviral drugs can prevent AIDS from developing.
If AIDS does develop, it means that the immune system is severely compromised, that is, weakened to the point where it can no longer successfully respond against most diseases and infections.
That makes the person living with AIDS vulnerable to a wide range of illnesses, including:
- oral thrush, a fungal condition in the mouth or throat
- cytomegalovirus (CMV), a type of herpes virus
- cryptococcal meningitis, a fungal condition in the brain
- toxoplasmosis, a brain condition caused by a parasite
- cryptosporidiosis, a condition caused by an intestinal parasite
- cancer, including Kaposi sarcoma (KS) and lymphoma
The shortened life expectancy linked with untreated AIDS isn’t a direct result of the syndrome itself. Rather, it’s a result of the diseases and complications that arise from having an immune system weakened by AIDS.
HIV and AIDS: What’s the connection?
To develop AIDS, a person has to have contracted HIV. But having HIV doesn’t necessarily mean that someone will develop AIDS.
Cases of HIV progress through three stages:
- stage 1: acute stage, the first few weeks after transmission
- stage 2: clinical latency, or chronic stage
- stage 3: AIDS
As HIV lowers the CD4 cell count, the immune system weakens. A typical adult’s CD4 count is 500 to 1,500 per cubic millimeter. A person with a count below 200 is considered to have AIDS.
How quickly a case of HIV progresses through the chronic stage varies significantly from person to person. Without treatment, it can last up to a decade before advancing to AIDS. With treatment, it can last indefinitely.
There’s currently no cure for HIV, but it can be managed. People with HIV often have a near-normal lifespan with early treatment with antiretroviral therapy.
Along those same lines, there’s technically no cure for AIDS currently. However, treatment can increase a person’s CD4 count to the point where they’re considered to no longer have AIDS. (This point is a count of 200 or higher.)
Also, treatment can typically help manage opportunistic infections.
HIV and AIDS are related, but they’re not the same thing.
HIV transmission: Know the facts
Anyone can contract HIV. The virus is transmitted in bodily fluids that include:
- vaginal and rectal fluids
- breast milk
Some of the ways HIV is transferred from person to person include:
- through vaginal or anal sex — the most common route of transmission
- by sharing needles, syringes, and other items for injection drug use
- by sharing tattoo equipment without sterilizing it between uses
- during pregnancy, labor, or delivery from a pregnant person to their baby
- during breastfeeding
- through “premastication,” or chewing a baby’s food before feeding it to them
- through exposure to the blood, semen, vaginal and rectal fluids, and breast milk of someone living with HIV, such as through a needle stick
The virus can also be transmitted through a blood transfusion or organ and tissue transplant. However, rigorous testing for HIV among blood, organ, and tissue donors ensures that this is very rare in the United States.
It’s theoretically possible, but considered extremely rare, for HIV to be transmitted through:
- oral sex (only if there are bleeding gums or open sores in the person’s mouth)
- being bitten by a person with HIV (only if the saliva is bloody or there are open sores in the person’s mouth)
- contact between broken skin, wounds, or mucous membranes and the blood of someone living with HIV
HIV does NOT transfer through:
- skin-to-skin contact
- hugging, shaking hands, or kissing
- air or water
- sharing food or drinks, including drinking fountains
- saliva, tears, or sweat (unless mixed with the blood of a person with HIV)
- sharing a toilet, towels, or bedding
- mosquitoes or other insects
It’s important to note that if a person living with HIV is being treated and has a persistently undetectable viral load, it’s virtually impossible to transmit the virus to another person.
Causes of HIV
HIV is a variation of a virus that can be transmitted to African chimpanzees. Scientists suspect the simian immunodeficiency virus (SIV) jumped from chimps to humans when people consumed chimpanzee meat containing the virus.
Once inside the human population, the virus mutated into what we now know as HIV. This likely occurred as long ago as the 1920s.
HIV spread from person to person throughout Africa over the course of several decades. Eventually, the virus migrated to other parts of the world. Scientists first discovered HIV in a human blood sample in 1959.
It’s thought that HIV has existed in the United States since the 1970s, but it didn’t start to hit public consciousness until the 1980s.
Causes of AIDS
AIDS is caused by HIV. A person can’t get AIDS if they haven’t contracted HIV.
Healthy individuals have a CD4 count of 500 to 1,500 per cubic millimeter. Without treatment, HIV continues to multiply and destroy CD4 cells. If a person’s CD4 count falls below 200, they have AIDS.
Also, if someone with HIV develops an opportunistic infection associated with HIV, they can still be diagnosed with AIDS, even if their CD4 count is above 200.
What tests are used to diagnose HIV?
Several different tests can be used to diagnose HIV. Healthcare providers determine which test is best for each person.
Antibody/antigen tests are the most commonly used tests. They can show positive results typically within 18–45 daysTrusted Source after someone initially contracts HIV.
These tests check the blood for antibodies and antigens. An antibody is a type of protein the body makes to respond to an infection. An antigen, on the other hand, is the part of the virus that activates the immune system.
These tests check the blood solely for antibodies. Between 23 and 90 daysTrusted Source after transmission, most people will develop detectable HIV antibodies, which can be found in the blood or saliva.
These tests are done using blood tests or mouth swabs, and there’s no preparation necessary. Some tests provide results in 30 minutes or less and can be performed in a healthcare provider’s office or clinic.
Other antibody tests can be done at home:
- OraQuick HIV Test. An oral swab provides results in as little as 20 minutes.
- Home Access HIV-1 Test System. After the person pricks their finger, they send a blood sample to a licensed laboratory. They can remain anonymous and call for results the next business day.
If someone suspects they’ve been exposed to HIV but tested negative in a home test, they should repeat the test in 3 months. If they have a positive result, they should follow up with their healthcare provider to confirm.
Nucleic acid test (NAT)
This expensive test isn’t used for general screening. It’s for people who have early symptoms of HIV or have a known risk factor. This test doesn’t look for antibodies; it looks for the virus itself.
It takes from 5 to 21 days for HIV to be detectable in the blood. This test is usually accompanied or confirmed by an antibody test.
Today, it’s easier than ever to get tested for HIV.
What’s the HIV window period?
As soon as someone contracts HIV, it starts to reproduce in their body. The person’s immune system reacts to the antigens (parts of the virus) by producing antibodies (cells that take countermeasures against the virus).
The time between exposure to HIV and when it becomes detectable in the blood is called the HIV window period. Most people develop detectable HIV antibodies within 23 to 90 days after transmission.
If a person takes an HIV test during the window period, it’s likely they’ll receive a negative result. However, they can still transmit the virus to others during this time.
If someone thinks they may have been exposed to HIV but tested negative during this time, they should repeat the test in a few months to confirm (the timing depends on the test used). And during that time, they need to use condoms or other barrier methods to prevent possibly spreading HIV.
Someone who tests negative during the window might benefit from post-exposure prophylaxis (PEP). This is medication taken after an exposure to prevent getting HIV.
PEP needs to be taken as soon as possible after the exposure; it should be taken no later than 72 hours after exposure but ideally before then.
Another way to prevent getting HIV is pre-exposure prophylaxis (PrEP). A combination of HIV drugs taken before potential exposure to HIV, PrEP can lower the risk of contracting or transmitting HIV when taken consistently.
Timing is important when testing for HIV.
Early symptoms of HIV
The first few weeks after someone contracts HIV is called the acute infection stage.
During this time, the virus reproduces rapidly. The person’s immune system responds by producing HIV antibodies, which are proteins that take measures to respond against infection.
During this stage, some people have no symptoms at first. However, many people experience symptoms in the first month or so after contracting the virus, but they often don’t realize HIV causes those symptoms.
This is because symptoms of the acute stage can be very similar to those of the flu or other seasonal viruses, such as:
- they may be mild to severe
- they may come and go
- they may last anywhere from a few days to several weeks
Early symptoms of HIV can include:
- swollen lymph nodes
- general aches and pains
- skin rash
- sore throat
- upset stomach
Because these symptoms are similar to common illnesses like the flu, the person who has them might not think they need to see a healthcare provider.
And even if they do, their healthcare provider might suspect the flu or mononucleosis and might not even consider HIV.
Whether a person has symptoms or not, during this period their viral load is very high. The viral load is the amount of HIV found in the bloodstream.
A high viral load means that HIV can be easily transmitted to someone else during this time.
Initial HIV symptoms usually resolve within a few months as the person enters the chronic, or clinical latency, stage of HIV. This stage can last many years or even decades with treatment.
HIV symptoms can vary from person to person.