HIV: What It Is, Causes, Diagnosis, Symptoms & Treatment

Sample blood collection tube with HIV test label
Sample blood collection tube with HIV test labelAdobe Stock

Even though HIV is just one of a vast number of viruses that infect people, there can still be a stigma surrounding it.

To break through that, experts answer some questions about the virus, such as what is HIV, how does it spread and what are the best HIV diagnostic tools. You’ll also discover the key HIV symptoms to look for, and what treatments are helping people who are living with HIV better manage the condition.

What is human immunodeficiency virus (HIV)?

HIV is a virus that attacks CD4 immune cells, which help your body fight infections, according to This puts you at increased risk of developing diseases and other infections.

The U.S. Centers for Disease Control and Prevention says that there are three stages of HIV infection:

  • Acute HIV infection
  • Chronic HIV infection
  • Acquired immunodeficiency syndrome (AIDS)

“AIDS is the most severe stage of HIV,” Cleveland Clinic ob-gyn Dr. Oluwatosin Goje said in a recent article. “People who are living with AIDS have badly damaged immune systems so they can get an increasing number of severe illnesses or opportunistic infections.”

How do you get HIV?

According to, HIV transmission occurs through direct contact with the body fluids of an HIV-positive person, including:

  • Blood
  • Breast milk
  • Vaginal or rectal fluids
  • Semen or pre-seminal fluids

HIV causes

The human immunodeficiency virus that causes HIV is believed to have first come from a version of the virus that infected chimpanzees. The CDC says it may have spread to humans as early as the late 1800s. explains person-to-person transmission causes new HIV infections, mainly by:

  • Vaginal or anal sex
  • Sharing injectable drug equipment

Less common ways of transmitting HIV include:

  • Exposure to a needle
  • HIV-contaminated blood transfusions or organ or tissue transplants
  • Oral sex or deep kissing, if open cuts, bleeding gums, sores, ulcers or sexually transmitted diseases are present
  • Being bitten by someone with HIV, or eating pre-chewed food after them
  • Pregnancy, giving birth or breastfeeding, which can cause the baby to get infected

How is HIV diagnosed? notes that your doctor will use the following HIV tests to diagnose the condition:

  • CD4 immune cell tests count how many of these infection-fighting cells are present
  • HIV viral load tests measure how much virus is present in your blood
  • HIV resistance testing helps your doctor pinpoint the best medications for your infection

HIV symptoms

According to, about 66% of people who get infected with HIV have at least some of the following symptoms within 2-4 weeks:

  • Fever
  • Lymph node swelling
  • Mouth ulcers
  • Chills
  • HIV rash
  • Sore throat
  • Tiredness
  • Night sweating
  • Aching muscles

Some people experience these same symptoms in Stage 2 HIV, while others are symptom-free. During Stage 3, people with AIDS may have the following symptoms:

  • Recurring night sweats
  • Rapid weight loss
  • Pneumonia
  • Diarrhea that lasts more than a week
  • Continuous lymph node swelling
  • Mouth, genital or anal sores
  • Unexplained fatigue
  • Memory loss
  • Depression
  • Neurological issues
  • Skin or mouth blotches that can be purple, pink, red or brown

While HIV symptoms in men and women are similar, U.S. National Library of Medicine and the Illinois Department of Public Health note there are some unique HIV symptoms in women:

  • Recurring vaginal yeast infections and other vaginal infections
  • Issues with menstruation
  • Entering menopause at a younger age
  • More intense hot flashes
  • More severe HIV medication side effects

HIV treatment

HIV medications

Antiviral therapy (ART) is a mixture of different antiviral medications that are taken daily. According to the U.S. National Institutes of Health, these include seven classes of antiviral medications that help lower the amount of HIV in the body.

PEP and PrEP HIV Prevention

When taken daily before exposure to HIV, the NIH says pre-exposure prophylaxis (PrEP) medication can help prevent the virus from infecting your system when you’re exposed.

“Taking PrEP medication as prescribed reduces the risk of contracting HIV through sexual contact by about 99%, and reduces the risk of getting HIV by at least 74% among people who inject drugs,” Goje advised.

There is also post-exposure prophylaxis (PEP), which is antiviral medication that must be taken within 72 hours of potential exposure to help prevent HIV infection.

Is HIV curable?

Dr. Merceditas Villanueva, director of the Yale School of Medicine’s AIDS Program, said in a recent Yale article that advancements in understanding the condition have come a long way -- but there is not yet a widespread cure.

"The message that we used to give in the early days of HIV was, 'Let's try to make your remaining days as comfortable as possible,'" Villanueva said. "Now, it’s treatable. It's not curable, but it is controllable."

Living with HIV

“With early diagnosis, surveillance and ART, those who are living with the virus can enjoy healthy and purposeful lives,” Goje explained. “They can also work and have meaningful relationships with partners, friends and family.”

Resources HIV Basics

U.S. Centers for Disease Control and Prevention: HIV Basics

Cleveland Clinic Health Essentials: Common Myths About HIV and AIDS

U.S. National Institutes of Health: Understanding HIV Fact Sheets

U.S. National Library of Medicine: HIV in Women

Illinois Department of Public Health Women’s Health: Facts About HIV/AIDS

Yale Medicine: How HIV Became the Virus We Can Treat

What This Means For You

While having HIV is no longer a death sentence, there is still no cure. Here, experts describe what HIV is, how you get it and what antiviral treatments help keep the disease under control.

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