How Does HIV Affect The Body? - Healthline

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Key takeaways

Human immunodeficiency virus (HIV) attacks CD4 “helper” T cells, weakening immunity and raising infection risk. AIDS (stage 3 HIV) occurs when CD4 drops below 200.
HIV spreads through blood, semen, vaginal fluid, and breast milk, such as during sex without condoms or sharing needles. Viral suppression means fewer than 200 HIV RNA copies per milliliter, which prevents sexual transmission.
HIV moves through acute, chronic, and AIDS stages, with the highest transmission risk during acute infection and possible negative antibody tests early on. Antiretroviral therapy uses multiple drugs to reach viral suppression, slow disease progression, and help immune recovery.

When HIV enters the body, it starts to attack the CD4 “helper cell” or T cell, which is an important part of the immune system.

When HIV is left untreated, even a minor infection such as a cold can be much more severe. This is because the body has difficulty responding to new infections.

Not only does HIV attack CD4 cells, it also uses the cells to make more of the virus. HIV destroys CD4 cells by using their replication machinery to create new copies of the virus. This ultimately causes the CD4 cells to swell and burst.

When the virus has destroyed a certain number of CD4 cells and the CD4 count drops below 200, the condition will have progressed to AIDS, also known as stage 3 HIV.

How is HIV transmitted?

HIV is transmitted through contact with the following bodily fluids. The following list is in order from most likely to least likely to lead to HIV transmission:

blood
semen
vaginal fluid
breast milk

Sex without a condom and sharing needles — even tattoo or piercing needles — can result in the transmission of HIV. However, if an HIV-positive person is able to achieve viral suppression, they won’t transmit HIV to others through sexual contact.

According to the Centers for Disease Control and Prevention (CDC), a person has reached viral suppression when they have fewer than 200 copies of HIV RNA per milliliter of blood.

There are three stages of HIV: acute HIV, chronic HIV, and AIDS (stage 3 HIV).

HIV doesn’t always multiply rapidly. Without treatment, it can take years for a person’s immune system to be affected enough to show signs of immune dysfunction and other infections.

Even without symptoms, HIV can still be present in the body and transmit to others. Receiving adequate treatment that results in viral suppression stops the progression of immune dysfunction and AIDS. Adequate treatment also helps a damaged immune system recover.

How does acute HIV affect the body?

Once a person contracts HIV, the acute infection takes place immediately.

Symptoms of the acute infection may take place days to weeks after the virus has been contracted. During this time, the virus is multiplying rapidly in the body, unchecked.

This initial HIV stage can result in flu-like symptoms. Examples of these symptoms include:

fever
headaches
rash
swollen lymph nodes
fatigue
myalgias, or muscle pain

The flu symptoms are due to the increase in copies of HIV and widespread infection in the body. During this time, the number of CD4 cells starts to fall very quickly. The immune system then kicks in, causing CD4 levels to rise once again. However, the CD4 levels may not return to their pre-HIV levels.

Additionally, not all people with HIV experience initial flu-like symptoms.

In addition to potentially causing symptoms, the acute stage is when people with HIV have the greatest chance of transmitting the virus to others. This is because HIV levels are very high at this time. The acute stage typically lasts between several weeks and months. It is also important to note that HIV antibody testing during this stage can be negative.

How does chronic HIV affect the body?

The chronic HIV stage is known as the latent or asymptomatic stage. During this stage, a person usually won’t have as many symptoms as they did during the acute phase. This is because the virus doesn’t multiply as quickly.

However, a person can still transmit HIV if the virus is left untreated and they continue to have a detectable viral load. Without treatment, the chronic HIV stage can last for many years before advancing to AIDS.

Advances in antiretroviral treatments have significantly improved the outlook for people living with HIV. With proper treatment, many people who are HIV-positive are able to achieve viral suppression and live long, healthy lives.

How does AIDS affect the body?

A normal CD4 count ranges from approximately 500 to 1,600 cells per cubic millimeter of blood (cells/mm3).

A person receives an AIDS diagnosis when they have a CD4 count of fewer than 200 cells/mm3.

A person may also receive an AIDS diagnosis if they’ve had an opportunistic infection or another AIDS-defining condition.

People with AIDS are vulnerable to opportunistic infections and common infections that may include tuberculosis, toxoplasmosis, and pneumonia.

People with weakened immune systems are also more susceptible to certain types of cancer, such as lymphoma and cervical cancer.

What are the factors that affect disease progression?

The most important factor affecting HIV progression is the ability to achieve viral suppression. Taking antiretroviral therapy regularly helps many people slow the progression of HIV and reach viral suppression.

However, several factors affect HIV progression, and some people progress through the phases of HIV more quickly than others.

Factors that affect HIV progression can include:

Ability to achieve viral suppression: The most important factor is whether someone can take their antiretroviral medications and achieve viral suppression.
Age when symptoms start: Being older can result in faster progresssion of HIV.
Health before treatment: If a person had other diseases, such as tuberculosis, hepatitis C, or other sexually transmitted infections (STIs), it can affect their overall health.
Timing of diagnosis: Another important factor is how soon a person received a diagnosis after they contracted HIV. The longer the time between their diagnosis and treatment, the more time the disease has to progress unchecked.
Lifestyle: A less healthy lifestyle, such as having an inadequate diet and experiencing severe stress, can affect HIV symptoms. Good nutrition and regular physical activity can help strengthen the immune system.

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

taking antiretroviral medications and achieving viral suppression
seeing a healthcare professional, as recommended, for HIV treatments
stopping the use of substances such as ethanol, methamphetamine, or cocaine
taking care of one’s health, including:
- having sex with condoms to help prevent acquiring other STIs
- trying to minimize stress
- regularly getting a good night’s sleep

How is HIV treated?

Treatments for HIV typically involve antiretroviral therapy. This isn’t a specific regimen, but instead a combination of three or four drugs. The Food and Drug Administration (FDA) has currently approved nearly 50 different medications to treat HIV.

Antiretroviral therapy works to prevent the virus from copying itself. This maintains immunity levels while slowing the progression of HIV.

Before prescribing medication, a healthcare professional will consider the following factors:

a person’s health history
the levels of the virus in the blood
possible side effects
costs
any pre-existing allergies

There are eight classes of HIV drugs, and a typical treatment regimen involves medications from different classes.

Most healthcare professionals will start people with HIV on a combination of three medications from at least two different drug classes. These classes are:

nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)
integrase strand transfer inhibitors (INSTIs)
non-nucleoside/non-nucleotide reverse transcriptase inhibitors (NNRTIs)
CCR5 antagonists (CCR5s)
fusion inhibitors
post-attachment inhibitors
capsid inhibitors
protease inhibitors

How can HIV be prevented?

HIV 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 the ways to help 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 into contact with body fluids, such as semen, vaginal fluid, blood, and breast milk

HIV is not transmitted by:

breathing the same air as a person living with HIV
getting bitten by a mosquito or other biting insect
hugging, holding hands with, kissing, or touching a person living with HIV
touching a door handle or toilet seat that someone who is HIV-positive has used

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

refraining from oral, anal, or vaginal sex
always using a latex barrier, such as a condom, when having oral, anal, or vaginal sex
avoiding sharing needles with other people

Healthcare professionals usually recommend that people get an HIV test at least once. If a person has had sex without condoms, had more than one sexual partner since their last HIV test, or shared needles with anyone in the past, testing should be at least once a year. People with past exposure to HIV would also benefit from episodic testing.

If a person has been exposed to HIV within the past 72 hours, they should consider postexposure prophylaxis, otherwise known as PEP.

People with ongoing exposure to HIV may benefit from preexposure prophylaxis (PrEP) and regular testing. PrEP is a daily pill, and the US Preventive Services Task Force recommends a PrEP regimen for everyone at increased risk of HIV.

Symptoms can take years to appear, which is why it’s so important to get tested regularly.

Takeaway

HIV affects the body’s immune system, which can lead to other infections and conditions.

If HIV is contracted, getting early treatment can prevent further transmission to others as well as progression of the disease. Treatment is vital to prevent the disease from developing into AIDS.

Advances in HIV treatments mean that people are living longer with the condition than ever before. Getting tested regularly and taking good care of one’s health can help reduce transmission.

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How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

10 things to know about HIV suppression. (2025).https://www.niaid.nih.gov/diseases-conditions/10-things-know-about-hiv-suppression
Battistini Garcia SA, et al. (2025). CD4 cell count and HIV.https://www.ncbi.nlm.nih.gov/books/NBK513289/
Broz D. (2021). Syringe services programs’ role in ending the HIV epidemic in the U.S.: Why we cannot do it without them.https://www.sciencedirect.com/science/article/pii/S0749379721003895
FDA approval of HIV medicines. (n.d.).https://hivinfo.nih.gov/understanding-hiv/infographics/fda-approval-hiv-medicines
Getting tested for HIV. (2025).https://www.cdc.gov/hiv/testing/
HIV infection and cancer risk. (2025).https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/hiv-fact-sheet
HIV testing overview. (2024).https://www.hiv.gov/hiv-basics/hiv-testing/learn-about-hiv-testing/hiv-testing-overview#
HIV treatment as prevention. (2024).https://www.cdc.gov/hivpartners/php/hiv-treatment/
Pirrone V, et al. (2013). Impact of age on markers of HIV-1 disease.https://pmc.ncbi.nlm.nih.gov/articles/PMC3625689/
Pre-exposure prophylaxis. (2025).https://www.hiv.gov/hiv-basics/hiv-prevention/using-hiv-medication-to-reduce-risk/pre-exposure-prophylaxis
Preexposure prophylaxis for the prevention of HIV infection: US Preventive Services Task Force recommendation statement. (2019).https://jamanetwork.com/journals/jama/fullarticle/2735509
Nutrition and people with HIV. (2024).https://www.hiv.gov/hiv-basics/living-healthy-with-hiv/taking-care-of-yourself/food-safety-and-nutrition
Taking your HIV medicine as prescribed. (2024).https://www.hiv.gov/hiv-basics/staying-in-hiv-care/hiv-treatment/taking-your-hiv-medications-every-day
The basics of HIV prevention. (2025).https://hivinfo.nih.gov/understanding-hiv/fact-sheets/basics-hiv-prevention
The stages of HIV infection. (2025).https://hivinfo.nih.gov/understanding-hiv/fact-sheets/stages-hiv-infection
U.S. statistics. (2025).https://www.hiv.gov/hiv-basics/overview/data-and-trends/statistics
Viral suppression and an undetectable viral load. (2025).https://www.hiv.gov/hiv-basics/staying-in-hiv-care/hiv-treatment/viral-suppression
What to start: Choosing an HIV treatment regimen. (2025).https://hivinfo.nih.gov/understanding-hiv/fact-sheets/what-start-choosing-hiv-treatment-regimen
Zhu X, et al. (2020). CD4 T helper cell subsets and related human immunological disorders.https://pubmed.ncbi.nlm.nih.gov/33126494/

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Medically reviewed by Ketan Patel, MD — Written by Rachel Nall, MSN, CRNA — Updated on January 23, 2026

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Key takeaways

How is HIV transmitted?

How does acute HIV affect the body?

How does chronic HIV affect the body?

How does AIDS affect the body?

What are the factors that affect disease progression?

How is HIV treated?

How can HIV be prevented?

Takeaway

How we reviewed this article:

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