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How HIV Affects the Body


Human immunodeficiency virus (HIV) is a virus that causes the condition acquired immunodeficiency syndrome (AIDS). The virus attacks a specific type of immune system cell in the body, known as CD4 helper lymphocyte cells. HIV destroys these cells, making it harder for your body to fight off other infections. When you have HIV, even a minor infection (like a cold) can be much more severe because your body has difficulty healing.

HIV is transmitted through contact with the following bodily fluids:

  • blood
  • breast milk
  • semen
  • vaginal fluid

Sexual contact and sharing contaminated needles — even tattoo or piercing needles — can result in the transmission of HIV.

Not only does HIV attack CD4 cells, it also uses the cells to make more of the virus. When the virus has destroyed a certain number of CD4 cells, doctors will call this stage AIDS. A person with AIDS is very vulnerable to infections, such as pneumonia. People with lowered immune systems can also get cancers, such as lymphoma.

HIV doesn’t always multiply rapidly. It can take years for a person’s immune system to be affected enough to have symptoms. A person with HIV will often progress through several phases before their condition is considered AIDS. Taking medications carefully can help to slow the disease’s progression.

Stages of HIV

Doctors have classified three HIV stages: acute HIV infection, chronic HIV infection, and AIDS.

Acute HIV infection

Once a person becomes infected with HIV, an acute infection will take place two to four weeks later. At this time, the virus is multiplying in the body, attacking CD4 cells. This initial infection can result in flu-like symptoms. Examples of these symptoms include:

  • fever
  • headache
  • rash

However, not all people with HIV experience initial flu-like symptoms. The flu symptoms are due to the increase of HIV viruses in the body. During this time, the amount of CD4 cells starts to fall very quickly. The immune system then kicks in, which causes CD4 levels to once again rise. However, the CD4 levels may not return to their preinfection height.

In addition to causing symptoms, the acute stage is when HIV is at its greatest risk for transmission to other people. This is because HIV levels are very high at this time. The acute stage typically lasts between several weeks and months.

Clinical latency

The chronic HIV infection stage is known as the latent or asymptomatic stage. During this stage, you usually won’t have as many symptoms as you did during the acute phase. The virus multiplies less quickly during the chronic stage. However, you can still transmit the HIV infection.

Without any treatment, the chronic HIV infection stage lasts anywhere from 10 to 12 years before advancing to AIDS. If a person is taking treatments for HIV, the chronic HIV infection stage may last several decades. According to, if you take treatments for HIV and your HIV levels are low, you can live a normal to nearly normal life span. It’s also possible that the infection will never progress to the AIDS phase.


A doctor diagnoses a person with AIDS when they have a CD4 count of less than 200 cells/3 (a measurement of the cells in the blood) and they’ve had an opportunistic infection, such as tuberculosis, cancer, or pneumonia. A normal CD4 count ranges from 500–1,600 cells/mm3 in healthy adults.

Unfortunately, when a person’s HIV progresses to AIDS, the survival rate is usually about three years.

What factors affect disease progression?

While HIV does progress in phases, some people go through the phases more quickly than others. Taking medications, known as antiretroviral therapy (ART), can slow this progression for more people. Factors that affect HIV progression can include:

  • Your age when your symptoms started: Being older can result in faster progression of HIV.
  • Your health before treatment: If you had other diseases, such as tuberculosis, hepatitis C, or other sexually transmitted diseases, it can affect your overall health.
  • How soon you were diagnosed after you were infected: The longer between your diagnosis and treatment, the faster the disease can progress.
  • Your lifestyle: Maintaining an unhealthy lifestyle, such as having a poor diet and experiencing severe stress, can aid HIV progression.
  • Whether you take your medications as prescribed
  • Your genetic history: Some people just seem to progress more quickly through their disease.

Some factors can delay or slow the progression of HIV. These include:

  • taking your ART medications as your doctor prescribes
  • seeing your doctor as recommended for HIV treatments
  • eating a healthy diet
  • taking care of yourself, including having protected sex, trying to minimize stress in your life, and sleeping regularly

Living a healthy lifestyle and seeing your doctor regularly can make a big difference in your overall health.

How is HIV treated?

Treatments for HIV typically involve ART. This isn’t a specific regimen, but instead a combination of several drugs. There are currently 25 different FDA-approved medicines to treat HIV. ART works to prevent the virus from copying itself. This maintains your immunity levels while slowing the progression of HIV.

Your doctor will take into consideration your health history, the levels of the virus in your blood, possible side effects, costs, and any allergies you may have before prescribing medications. There are six classes of HIV drugs. Most doctors will start you on a combination of three medications from at least two different drug classes. These classes are:

  • CCR5 antagonists (CCR5s)
  • fusion inhibitors
  • integrase stand transfer inhibitors (INSTIs)
  • non-nucleoside reverse transcriptase inhibitors (NNRTIs)
  • nucleoside reverse transcriptase inhibitors (NRTIs)
  • protease inhibitors

Your doctor may prescribe several different medication types before you find the best regimen for you.

How is HIV prevented?

HIV is an especially dangerous virus because it doesn’t cause a lot of outward or noticeable symptoms until the disease has progressed. For this reason, it’s important to understand how HIV is transmitted and ways you can work to prevent transmission.

HIV can be transmitted by: 

  • having sex, including oral, vaginal, and anal sex
  • sharing needles, including tattoo needles, needles used for body piercing, and needles used for injecting drugs
  • coming in contact with body fluids, such as blood, semen, vaginal fluid, and breast milk

HIV is not transmitted by:

  • breathing the same air as an infected person
  • getting bitten by a mosquito or other biting insect
  • hugging, holding hands with, kissing, or touching an infected person
  • touching a door handle or toilet seat an infected person has used

Keeping this in mind, some of the ways you can prevent HIV include:

  • refraining from oral, anal, or vaginal sex (known as the abstinence method)
  • always using a latex barrier, such as a condom, when you have oral, anal, or vaginal sex
  • never sharing needles with others

If you’ve had unprotected sex or shared needles with anyone in the past, doctors usually recommend getting an HIV test at least once a year. Symptoms can take years to appear, which is why it’s so important to get tested regularly.


Advances in HIV treatments mean that people can live longer with the condition. Getting tested regularly and taking good care of yourself is vital to keeping your disease from progressing to the AIDS phase. 

Content licensed from:

Written by: Rachel Nall
Medically reviewed on: Sep 28, 2016: Timothy J. Legg, PhD, CRNP

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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