HIV and AIDS: Symptoms, Transmission, and Treatment
Author: Disabled World (DW)
Updated/Revised Date: 3 Nov 2026
Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics
Synopsis
Learn how HIV and AIDS differ, how the virus is transmitted, common symptoms, post-exposure treatment options, and key global statistics on infection.
At a Glance
- 1 - HIV is not spread through tears, sweat, saliva, urine, or feces.
- 2 - PEP must begin within 72 hours of exposure and be taken for 28 days.
- 3 - About 40.9 million people worldwide were living with HIV in 2025, according to UNAIDS.
- 4 - A nucleic acid test can usually detect HIV 10 to 33 days after exposure, sooner than other tests.
Topic Definition
- HIV and AIDS
Human Immunodeficiency Virus (HIV) is a virus that infects only humans and gradually weakens the immune system by destroying the cells that defend the body against infection and disease. Acquired Immunodeficiency Syndrome (AIDS) is the advanced stage of that infection, diagnosed by a doctor when a person who is HIV positive develops a low CD4 count or one of the illnesses defined by the Centers for Disease Control and Prevention. Because a weakened immune system can no longer control opportunistic infections, AIDS is classified as a syndrome rather than a single disease, and it typically takes eight to eleven years for HIV to progress to this point without treatment.
Overview
Human immunodeficiency virus (HIV) is a virus that attacks the body's immune system, especially the CD4 cells (T cells) that help the body fight infection. Without treatment, HIV gradually weakens the immune system until the body can no longer fight off opportunistic infections and certain cancers. Acquired immunodeficiency syndrome (AIDS) is the most advanced stage of HIV infection. A doctor diagnoses AIDS when a person with HIV has a CD4 count below 200 cells per cubic millimeter of blood or develops one of the AIDS-defining illnesses listed by the Centers for Disease Control and Prevention (CDC).
Testing positive for HIV does not mean that a person has AIDS. There is no cure for HIV, but antiretroviral therapy (ART) can control the virus. People with HIV who take their medicine as prescribed and keep an undetectable viral load can live long, healthy lives and do not pass HIV to their sexual partners, a principle known as "undetectable equals untransmittable."
Difference Between HIV and AIDS
HIV is the virus. It is spread mainly through sex without a condom or HIV prevention medicine, by sharing needles or other drug-injection equipment, and from mother to child during pregnancy, childbirth or breastfeeding. Without treatment, it usually takes years, on average about 10, before HIV weakens the immune system enough to cause AIDS.
AIDS is the late stage of untreated HIV infection, when the immune system is badly damaged and the body has trouble fighting infections and diseases. With today's treatment, most people with HIV never develop AIDS.
What HIV and AIDS Stand For
- H - Human: this virus infects only human beings.
- I - Immunodeficiency: HIV weakens the immune system by destroying cells that fight disease and infection, leaving it "deficient."
- V - Virus: a virus can reproduce only by taking over a cell in the body of its host.
- A - Acquired: AIDS is not inherited; it develops after birth as a result of HIV infection.
- I - Immuno: the immune system includes all the organs and cells that work to fight off infection or disease.
- D - Deficiency: the immune system is not working the way it should.
- S - Syndrome: AIDS is a collection of signs and symptoms rather than a single disease, because it involves a wide range of complications.
Symptoms of HIV
Within 2 to 4 weeks after infection, many people have flu-like symptoms such as fever, chills, rash, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes and mouth ulcers. This stage is called acute HIV infection. Others notice nothing at all. Because these symptoms are common to many viral illnesses, the only way to know for sure is to get tested.
After the acute stage, HIV enters a chronic stage that may cause few or no symptoms for years while the virus continues to damage the immune system. Without treatment, the person may then develop AIDS, with symptoms such as rapid weight loss, recurring fever, extreme tiredness, long-lasting diarrhea, pneumonia and opportunistic infections.
Testing for HIV
The CDC recommends that everyone aged 13 to 64 be tested for HIV at least once as part of routine health care, and that people at higher risk be tested at least once a year. No test can detect HIV immediately after infection. A nucleic acid test (NAT) can usually detect HIV 10 to 33 days after exposure, a laboratory antigen/antibody test 18 to 45 days after exposure, and rapid tests and self-tests 18 to 90 days after exposure, so a negative result soon after a possible exposure should be repeated [HIV.gov, n.d.].
How HIV Is Transmitted
HIV is spread through certain body fluids from a person who has HIV and a detectable viral load: blood, semen and pre-seminal fluid, rectal fluids, vaginal fluids and breast milk. Anal and vaginal sex without a condom or HIV prevention medicine are the most common ways HIV spreads, and anal sex carries the highest risk. Sharing needles, syringes or other drug-injection equipment is another efficient way to spread the virus. Oral sex carries a very low risk. In the United States, donated blood and organs are screened, so the risk from transfusions and transplants is extremely low.
A mother with HIV can pass the virus to her baby during pregnancy, birth or breastfeeding, but taking HIV medicine as prescribed throughout pregnancy and childbirth, and giving the baby HIV medicine after birth, can reduce the risk to 1 percent or less.
HIV is not spread through tears, sweat, saliva, urine or feces, or through hugging, shaking hands, sharing toilets or dishes, or insect bites.
Treatment
Antiretroviral therapy (ART) uses a combination of HIV medicines, often in a single daily pill, and long-acting injections given every one or two months are also available. ART is recommended for everyone with HIV, starting as soon as possible after diagnosis. It cannot cure HIV, but it lowers the amount of virus in the blood (the viral load) to very low levels, protects the immune system and prevents sexual transmission.
Preventing HIV: PrEP and PEP
Pre-exposure prophylaxis (PrEP) is medicine taken by people who do not have HIV to prevent infection. PrEP is available as a daily pill, as an injection every two months (cabotegravir), and since June 2025 as an injection given twice a year (lenacapavir). When taken as prescribed, PrEP reduces the risk of getting HIV from sex by about 99 percent.
Post-exposure prophylaxis (PEP) means taking HIV medicines after a possible exposure, such as sex without a condom, sharing needles, sexual assault, or a needlestick injury at work. PEP must be started as soon as possible, ideally within 24 hours and no later than 72 hours after exposure, and taken every day for 28 days. Under CDC guidelines updated in May 2025, the preferred regimens are bictegravir/emtricitabine/tenofovir alafenamide, a single daily pill, or dolutegravir combined with tenofovir and emtricitabine or lamivudine. Side effects such as nausea, diarrhea, headache and tiredness are usually mild. People who may have repeated exposures should talk with a doctor about moving from PEP to PrEP [Centers for Disease Control and Prevention, 2025].
Health care workers, police officers and others have used PEP since the mid-1990s after accidental exposures, most often needlestick injuries. A CDC-led study published in 1997 found that taking zidovudine (AZT) after a needlestick injury lowered the risk of infection by about 80 percent [Cardo et al., 1997].
HIV and AIDS Facts and Statistics
- About 40.9 million people worldwide were living with HIV in 2025, and about 1.2 million people acquired HIV that year [UNAIDS, 2026].
- About 630,000 people died from AIDS-related illnesses in 2024, about 70 percent fewer than at the peak in 2004 [UNAIDS, 2025].
- Eastern and southern Africa remains the region most affected by HIV.
- In the United States, about 1.2 million people are living with HIV, and about 1 in 8 of them do not know it.
Frequently Asked Questions
Can HIV be cured completely?
There is no complete cure for HIV, but antiretroviral therapy can control the virus, protect the immune system, and allow people to live long and healthy lives.
How soon after exposure can HIV be detected by a test?
Depending on the test, HIV can usually be detected 10 to 33 days (nucleic acid test) to 18 to 90 days (antigen/antibody and antibody tests) after exposure, so a negative test soon after exposure should be repeated.
Is there a vaccine to prevent HIV?
As of the latest guidance there is no approved vaccine that prevents HIV, so prevention relies on safe practices, testing, and preventive medication.
What is the difference between PEP and PrEP?
PEP is taken after possible exposure to reduce infection risk, while PrEP is taken regularly beforehand by people at ongoing risk to prevent infection.
Can people with HIV live a normal life span?
With early diagnosis and consistent treatment, many people with HIV now have a life expectancy close to that of people without the virus.
Does having HIV always mean a person has AIDS?
No, being HIV positive does not mean a person has AIDS, since AIDS is a later stage diagnosed only when specific medical criteria are met.
Can HIV be passed through everyday contact such as hugging or sharing utensils?
No, HIV is not spread through casual contact like hugging, shaking hands, or sharing utensils, because saliva and sweat do not carry the virus.
What does undetectable equals untransmittable mean?
It means a person with HIV who takes treatment and keeps an undetectable viral load cannot pass HIV to sexual partners. Large studies have confirmed this, which is why starting treatment early is so important.
References
- Cardo, D. M., et al. (1997). A case-control study of HIV seroconversion in health care workers after percutaneous exposure. New England Journal of Medicine, 337(21), 1485-1490.
- Centers for Disease Control and Prevention. (2025). Updated guidelines for antiretroviral postexposure prophylaxis after sexual, injection drug use, or other nonoccupational exposure to HIV - United States, 2025. MMWR Recommendations and Reports, 74(1).
- HIV.gov. (n.d.). HIV testing overview.
- UNAIDS. (2025). Global HIV and AIDS statistics: Fact sheet 2025.
- UNAIDS. (2026). Global HIV and AIDS statistics: Fact sheet 2026.
Curated and edited by Ian C. Langtree, Founder and Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team. Last updated: