HIV

This article is about the virus. For the infection caused by the virus, see HIV/AIDS. For other uses, see HIV (disambiguation).

Human immunodeficiency virus (HIV) is a type of virus called a Lentivirus, which means "slow virus". This is a kind of retrovirus. It infects the human immune system, which is the system in the body which fights off infections.

Human immunodeficiency viruses
Scanning electron micrograph of HIV-1 (in green) budding from cultured lymphocyte. Multiple round bumps on cell surface represent sites of assembly and budding of virions.
Scientific classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Pararnavirae
Phylum:	Artverviricota
Class:	Revtraviricetes
Order:	Ortervirales
Family:	Retroviridae
Subfamily:	Orthoretrovirinae
Genus:	Lentivirus
Groups included
Human immunodeficiency virus 1 Human immunodeficiency virus 2
Other lentiviruses
Bovine immunodeficiency virus Caprine arthritis encephalitis virus Equine infectious anemia virus Feline immunodeficiency virus Jembrana disease virus Puma lentivirus Simian immunodeficiency virus Visna-maedi virus

HIV and AIDS explained in a simple way

Percentage of adults that are infected with HIV per country at the end of 2005

  15–50% (15-50 people out of 100)

  5–15% (5-15 people out of 100)

  1–5% (1-5 people out of 100)

  0.5–1.0% (1-2 people out of 200)

  0.1–0.5% (1-5 people out of 1000)

  <0.1% (less than 1 person out of 1000)

  Greenland no data

Diagram of the immature and mature forms of HIV

HIV may cause AIDS. This kills the white blood cells which a healthy body uses to fight diseases.

African Americans, gay and bisexual men, black women, transgender women and drug users are most affected by the disease.^[1]

South Africa, Lesotho, Swaziland, Botswana, Namibia, Zambia and Zimbabwe have the highest rate of HIV in the world.^[2]

How people get infected

A person can get infected with HIV if any body liquid with the virus gets into their body. The body liquids that carry HIV are blood, semen, liquid from the vagina, and breast milk.

Most often, people get HIV through the vagina or anus during sex. However, the virus may get into the body anywhere that there is injured skin.

Some common ways to get HIV include:

• A person with HIV can give a sexual partner the virus if they have unprotected sex. That means having sexual intercourse without a condom.
• A person can get HIV if they use the same needle as a person with HIV, which most often happens when injecting drugs or getting a tattoo.
• Babies can get the virus from their mothers when they are born or when they are breastfeeding. A baby may be protected from getting HIV this way if their mother takes certain medications while she is pregnant.
• In the past, blood transfusions using HIV-infected blood was a common cause of HIV. The blood had been taken from people with HIV infections. Now, in the developed world screening of blood products for HIV has mostly stopped this happening. However, people may still get HIV from blood transfusions in less-developed countries if the blood is not screened.

A person cannot get infected with HIV from non-sexual touching, like a hug or handshake, or touching or swallowing someone else's saliva. A person cannot get HIV from an insect bite, a cough, or a sneeze.^[3] People also cannot get HIV from touching light switches, using toilets, or drinking from the same glass as a person with HIV.

Data

Comparison of HIV species

Species	Virulence	Infectivity	Prevalence	Inferred origin
HIV-1	High	High	Global	Common Chimpanzee
HIV-2	Lower	Low	West Africa	Sooty Mangabey

Estimated per-act risk for acquisition of HIV by exposure route ^[4][5][6]

Exposure Route [7]	Estimated infections per 10,000 exposures to an infected source [8]
Blood transfusion [Being given blood in a transfusion]	9,000 (90%)[9]
Mother-to-child, including pregnancy, childbirth and breastfeeding (without treatment) [Mother giving her child or unborn child HIV, if she does not take medications to prevent giving the child HIV]	2,500 (25%)[10]
Mother-to-child, including pregnancy, childbirth and breastfeeding (with optimal treatment) [Mother giving her child or unborn child HIV, if she takes the best possible medications to prevent giving the child HIV]	100–200 (1%–2%)[10]
Needle-sharing injection drug use [People sharing the same needle to inject illegal drugs]	67 (0.67%)[11]
Percutaneous needle stick [Getting stuck by a needle used on a person with HIV - for example, in healthcare]	30 (0.30%)[12]
Receptive anal intercourse (2009 and 2010 studies) [Receiving anal sex]	170 (1.7%)‡ [30–890][13] / 143 [48–285][6]
Receptive anal intercourse (based on data of a 1992 study) [Receiving anal sex]	50 (0.5%)[14][15]
Insertive anal intercourse for uncircumcised men (2010 study) [An uncircumsized man giving anal sex]	62 (0.62%)a [7–168][6]
Insertive anal intercourse for circumcised men (2010 study) [A circumsized man giving anal sex]	11 (0.11%)a [2–24][6]
Insertive anal intercourse (based on data of a 1992 study) [Giving anal sex]	6.5 (0.065%)[14][15]
Low-income country female-to-male [A woman giving a man HIV through sexual activity; rate is for low-income countries]	38 (0.38%)‡ [13–110][13]
Low-income country male-to-female [A man giving a woman HIV through sexual activity; rate is for low-income countries]	30 (0.3%)‡ [14–63][13]
Receptive (female) penile-vaginal intercourse [A woman receiving sexual intercourse from a man]	10 (0.1%)[14][15][16]
Insertive (male) penile-vaginal intercourse [A man giving sexual intercourse to a woman]	5 (0.05%)[14][15]
Fellating a man [Performing oral sex on a man]	1 (0.01%)†b[15]
Man being fellated [A man receiving oral sex]	0.5 (0.005%)†b[15]

^a Other studies found insufficient evidence that male circumcision protects against HIV infection among men who have sex with men^[17][18]

^b Oral trauma, sores, inflammation, concomitant sexually transmitted infections, ejaculation in the mouth, and systemic immune suppression may increase HIV transmission rate.^[19]

^† "best-guess estimate"

^‡ Pooled transmission probability estimate.

Bracketed values represent 95% confidence interval.

Treatment

Drug treatment

HIV infects and kills cells in the body that prevent disease, which makes people with HIV more prone to illness. There are many drugs available to treat HIV, but there is no cure for HIV, though lots of research is in progress. Drugs that treat HIV are called antiretroviral therapy (ART) or highly-active antiretroviral therapy (HAART). HAART treatment generally consists of a combination of two or three drugs, each of which target a different part of the HIV virus life cycle. Together, HAART slows the progression of the HIV virus in the body.^[20] HAART also prevents the HIV virus from multiplying and destroying CD4 T cells, which are necessary to help protect the body from infections and cancer.^[21]

It is recommended to start HAART if a person has HIV and has a CD4 cell count of less than or equal to 350 cells/mm3. This number can be determined by a doctor.^[20] A person’s age, sex, and other infections determine which treatment they should take.^[20] These medication regimens can help people living with HIV live longer, healthier lives, and can also help prevent the HIV infection from advancing to AIDS.^[22]

Symptoms of acute HIV infection

General treatment

There has been controversy surrounding when the correct time to start therapy should be after a person discovers that they have HIV. Recently, the answer has been that earlier treatment is recommended.^[23] This is because, first, effective therapy can prevent non-AIDS-related deaths. Second, therapy can prevent harm to a person’s immune system. Third, therapy can help prevent transmission of HIV to others, and can therefore reduce HIV prevalence overall.^[23] Although there are some negative side effects of antiretroviral medications, the benefits of therapy usually outweigh the negative effects.

Effects of therapy

Patients on HAART have reported significant improvements in physical health, emotional health, mental health, and daily function compared to HIV-positive patients not yet on treatment.^[24] Most research has occurred in developing countries, and little research has been done on the impacts of ART on household wellbeing.^[24]

Although HAART can be an effective means to treating HIV, there can be many negative side effects. Negative side effects can vary by drug, by ethnicity, and by drug interactions in the body. The following list contains the most common and serious negative side effects associated with HAART medications to treat HIV.^[25]

Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

• Lactic acidosis, hepatic steatosis, and body fat redistribution (lipodystrophy)
• Fever, headache, rash, nausea, vomiting, diarrhea, fatigue

Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs)

• Rash, Stevens-Johnson syndrome, and toxic epidermal necrolysis
• Fatigue, mood changes, liver function, insomnia
• May have significant interactions with other drugs; dosage adjustments would be required

Protease Inhibitors (PIs)

• Metabolic abnormalities including dyslipidemia, hyperglycemia, insulin resistance, and lipodystrophy
• May increase risk of bleeding in hemophiliacs
• Rash, diarrhea, vomiting, taste perversion, fatigue
• May have significant interactions with other drugs; dosage adjustment would be required

Fusion Inhibitors

• Injection site reactions, neutropenia, increased frequency of pneumonia

Chemokine Coreceptor Antagonists

• Diarrhea, nausea, fatigue, dizziness, headache, liver function, joint pain

Integrase Inhibitors

• Nausea, diarrhea, headache, rash

Pharmacokinetic Enhancers

• Increased serum creatinine, proteinuria, nausea, diarrhea ^[25]

Alternative therapy

Many people living with HIV have tried using alternative treatment methods, known as complementary and alternative medicine (CAM). Some types of CAM include stress management, natural health products, massage/therapeutic touch, acupuncture, and homeopathy.^[26] Stress management can increase quality of life for a person with HIV.^[26] Even with little evidence of its effectiveness, many people chose to try CAM because of the many negative side effects associated with HAART and the few negative side effects associated with CAM. Some HIV-infected people also try herbal medicines to treat HIV, but there has been no evidence showing any positive outcomes with the use of herbal remedies.^[27]

Another type of alternative therapy for treating HIV is micronutrient supplementation. Micronutrients are vitamins and minerals, so these supplements would be in the form of a general daily multivitamin. These supplements have been proven to help treat HIV because HIV can cause micronutrient deficiencies, so the supplements can help replenish these needed vitamins and minerals. Although the supplements may not help ease all negative symptoms, they offer some benefits and are safe for HIV-infected patients.^[27] Supplements are also safe for HIV-infected pregnant women and their children. Specifically, vitamin A and zinc have shown positive health effects.^[27] There are no major negative side effects of vitamin and mineral supplements.^[28]

Alternative therapies can help to reduce symptoms of diseases like HIV, but do not cure the disease, or stop the disease from spreading to other people.

PREP

"PREP" or "PrEP" is pre-exposure prophylaxis. This means a person takes a drug before having risky sex. The drug 'Truvada' is a combination of two different anti-viral treatments: tenofovir and emtricitabine.^[29] Truvada is very expensive, and was not available on the UK's National Health Service before 2016. A study, published in The Lancet in 2023 found that PrEP reduced the chances of getting HIV by almost 87% and recommended that it should be more easily available.^[30]

External websites

• AIDS-HIV Resources and guidelines for prevention Archived 2010-01-28 at the Wayback Machine
• University of California, Santa Barbara's SexInfo^{[permanent dead link]} This article provides basic information about HIV/AIDS in a way that is easy to understand. This site also has an article that provides A Personal Guide for Preventing AIDS Transmission^{[permanent dead link]}.
• AIDS Education Global Information System (AEGiS)