Why AIDS is an immune deficiency?
After four decades in the global human immunodeficiency virus (HIV) epidemic, the medical community has learned a great deal about HIV since the AIDS crisis that began in 1981, when the first case was identified. Given new treatments—and with proper care—many people diagnosed with HIV can live a normal life. Show
HIV is a virus that’s most often spread through blood and bodily fluids, typically but not exclusively through sexual contact. It attacks and kills a certain type of white blood cell in the body, which weakens the immune system and makes it hard for people to fight off illnesses and infections. AIDS (acquired immune deficiency syndrome) is an advanced form of immune deficiency caused by HIV. About 1.2 million Americans are living with HIV, and nearly 38,000 people are diagnosed each year. HIV can affect people of all ages, races and genders, but certain groups are impacted more than others. HIV disproportionately affects Black and Latinx Americans. And more than two-thirds of people who are newly diagnosed in the U.S. are men who have sex with men (including gay and bisexual men). It’s estimated that roughly 13% of people with HIV don’t know that they have the disease. Treatments may help people with HIV maintain their health and quality of life for decades, but people with undiagnosed HIV don’t know that they should seek treatment. This is why it’s important for people to learn their HIV status so that if they have the condition, they can start treatment early, before experiencing complications. “We have effective and simple combination antiretroviral treatment [ART] in a single tablet. Although we don’t have a cure for HIV, we can achieve a functional cure and prolong the years and quality of life of people living with HIV,” says Lydia Aoun-Barakat, MD, medical director of the Yale HIV Ambulatory Center. “The key is to get tested at least once for HIV, and if the person is at risk, they can be on pre-exposure prophylaxis [PrEP] therapy. If they are positive, they should seek a rapid start of ART.”
HIV is a retrovirus that infects humans. The virus attaches itself to specific white blood cells, called CD4 T cells. These cells are important components of the immune system, helping to fight infections in the body. But HIV renders them harmful, triggering those cells to make multiple copies of itself while gradually destroying the T cells. A healthy person may have, on average, 750-1,500 CD4 T cells per microliter of blood. In someone with HIV, as that number starts to decline over time, the immune system has trouble warding off illness. Once people with HIV have fewer than 200 CD4 T cells per microliter of blood, they may experience serious illness or infection, and their diagnosis changes from HIV infection to AIDS. When HIV was first documented, in the early 1980s, there were no effective treatments for it, so the disease often progressed to AIDS, leading to the death of millions of people. Today, the disease has moved from fatal to treatable; medications may help people with HIV live for decades with a good quality of life.
The virus is spread through bodily fluids, including blood, semen, vaginal fluids, and breast milk. It’s considered primarily a sexually transmitted disease, but this isn’t the only way that people may come into contact with these bodily fluids. People are commonly exposed to the virus by:
People experience different symptoms at different stages of the disease. When people are first exposed to HIV, about half of them don’t initially notice any signs of illness. The other half have flu-like symptoms two to four weeks after they’re infected, then recover. Other symptoms may include:
Once the initial symptoms disappear, people who don’t know their HIV status (or aren’t treated) may experience mild illness or may have no noticeable symptoms for about a decade. Even in those with no symptoms, levels of CD4 T cells drop over time.
When someone’s T-cell count falls below 200 per microliter of blood, they may develop infections and illnesses including:
A definitive HIV diagnosis is made with a blood test. Health care providers will also take a medical history, asking about personal health history, sexual partners, and other lifestyle habits that may increase risk. Because initial symptoms may be vague or not present, a physical exam usually won’t help doctors diagnose HIV. The routine HIV test may not become positive for several weeks after infection. For this reason, people who suspect that they’ve been exposed to HIV may need to get re-tested after several weeks or have a specific test for the HIV viral load in the blood. Different blood tests look for:
It’s also possible to test oral fluids, such as saliva, for HIV.
The Centers for Disease Control and Prevention (CDC) recommends:
Routine HIV testing at health care visits can be helpful, since it is not uncommon for a person to be unaware that they have the virus. Starting treatment as early as possible improves the outlook.
Doctors recommend treatment for all people with HIV, including those who are newly diagnosed, no matter what their CD4 T cell counts are. Treatment may reduce HIV to undetectable levels, improve CD4 T cell counts, and prevent HIV from progressing to AIDS. People must take medication daily and consistently to prevent HIV from becoming drug-resistant. Common HIV therapies include:
Antiretroviral therapy may also reduce the risk of HIV among certain people.
There is no cure for HIV, but it can be managed as a chronic condition. People who are living with HIV who take their medication daily and see their doctors regularly may enjoy a fairly normal life. People who don’t seek treatment for HIV or AIDS may only live for about 3 years after the onset of AIDS.
Yale established the first HIV clinic in the state of Connecticut and continues to care for the largest cohort of people living with HIV. “We provide a comprehensive and interdisciplinary team approach to HIV and offer state-of-the-art treatment with access to new drugs and clinical trials, in addition to cutting edge research,” says Dr. Barakat. “Furthermore, Yale was the first clinic in the state to offer PrEP to persons at risk for HIV. Through our talented and experienced providers and researchers, along with community partnership, Yale aspires to be in the forefront to ending the HIV epidemic.” Related Fact SheetsShowing 4 of 147
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