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HUMAN IMMUNODEFICIENCY VIRUS INFECTION AND ACQUIRED IMMUNE DEFICIENCY SYNDROME (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness . Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system , increasing the risk of common infections like tuberculosis , as well as other opportunistic infections , and tumors that rarely affect people who have working immune systems. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with weight loss .

HIV
HIV
is spread primarily by unprotected sex (including anal and oral sex ), contaminated blood transfusions , hypodermic needles , and from mother to child during pregnancy , delivery, or breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV. Methods of prevention include safe sex , needle exchange programs , treating those who are infected , and male circumcision . Disease in a baby can often be prevented by giving both the mother and child antiretroviral medication . There is no cure or vaccine ; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. Treatment is recommended as soon as the diagnosis is made. Without treatment, the average survival time after infection is 11 years.

In 2016 about 36.7 million people were living with HIV
HIV
and it resulted in 1 million deaths. There were 300,000 fewer new HIV
HIV
cases in 2016 than in 2015. Most of those infected live in sub-Saharan Africa . Between its discovery and 2014 AIDS has caused an estimated 39 million deaths worldwide. HIV/AIDS
HIV/AIDS
is considered a pandemic —a disease outbreak which is present over a large area and is actively spreading. HIV
HIV
is believed to have originated in west-central Africa during the late 19th or early 20th century. AIDS was first recognized by the United States Centers for Disease Control and Prevention (CDC) in 1981 and its cause— HIV
HIV
infection—was identified in the early part of the decade.

HIV/AIDS
HIV/AIDS
has had a great impact on society, both as an illness and as a source of discrimination . The disease also has large economic impacts . There are many misconceptions about HIV/AIDS
HIV/AIDS
such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving religion including the Catholic Church\'s position not to support condom use as prevention. It has attracted international medical and political attention as well as large-scale funding since it was identified in the 1980s. Play media Video explanation

CONTENTS

* 1 Signs and symptoms

* 1.1 Acute infection * 1.2 Clinical latency * 1.3 Acquired immunodeficiency syndrome

* 2 Transmission

* 2.1 Sexual * 2.2 Body fluids * 2.3 Mother-to-child

* 3 Virology * 4 Pathophysiology

* 5 Diagnosis

* 5.1 HIV
HIV
testing * 5.2 Classifications

* 6 Prevention

* 6.1 Sexual contact * 6.2 Pre-exposure * 6.3 Post-exposure * 6.4 Mother-to-child * 6.5 Vaccination
Vaccination

* 7 Treatment

* 7.1 Antiviral therapy * 7.2 Opportunistic infections * 7.3 Diet * 7.4 Alternative medicine
Alternative medicine

* 8 Prognosis * 9 Epidemiology

* 10 History

* 10.1 Discovery * 10.2 Origins

* 11 Society and culture

* 11.1 Stigma * 11.2 Economic impact * 11.3 Religion and AIDS * 11.4 Media portrayal * 11.5 Criminal transmission * 11.6 Misconceptions

* 12 Research * 13 References * 14 Further reading * 15 External links

SIGNS AND SYMPTOMS

Main article: Signs and symptoms of HIV/AIDS
Signs and symptoms of HIV/AIDS

There are three main stages of HIV
HIV
infection: acute infection, clinical latency and AIDS.

ACUTE INFECTION

Main symptoms of acute HIV
HIV
infection

The initial period following the contraction of HIV
HIV
is called acute HIV, primary HIV
HIV
or acute retroviral syndrome. Many individuals develop an influenza-like illness or a mononucleosis-like illness 2–4 weeks post exposure while others have no significant symptoms. Symptoms occur in 40–90% of cases and most commonly include fever , large tender lymph nodes , throat inflammation , a rash , headache, and/or sores of the mouth and genitals. The rash, which occurs in 20–50% of cases, presents itself on the trunk and is maculopapular , classically. Some people also develop opportunistic infections at this stage. Gastrointestinal symptoms, such as vomiting or diarrhea may occur. Neurological symptoms of peripheral neuropathy or Guillain–Barré syndrome also occurs. The duration of the symptoms varies, but is usually one or two weeks.

Due to their nonspecific character, these symptoms are not often recognized as signs of HIV
HIV
infection. Even cases that do get seen by a family doctor or a hospital are often misdiagnosed as one of the many common infectious diseases with overlapping symptoms. Thus, it is recommended that HIV
HIV
be considered in people presenting an unexplained fever who may have risk factors for the infection.

CLINICAL LATENCY

The initial symptoms are followed by a stage called clinical latency, asymptomatic HIV, or chronic HIV. Without treatment, this second stage of the natural history of HIV
HIV
infection can last from about three years to over 20 years (on average, about eight years). While typically there are few or no symptoms at first, near the end of this stage many people experience fever, weight loss, gastrointestinal problems and muscle pains. Between 50 and 70% of people also develop persistent generalized lymphadenopathy , characterized by unexplained, non-painful enlargement of more than one group of lymph nodes (other than in the groin) for over three to six months.

Although most HIV-1 infected individuals have a detectable viral load and in the absence of treatment will eventually progress to AIDS, a small proportion (about 5%) retain high levels of CD4+ T cells (T helper cells ) without antiretroviral therapy for more than 5 years. These individuals are classified as HIV
HIV
controllers or long-term nonprogressors (LTNP). Another group consists of those who maintain a low or undetectable viral load without anti-retroviral treatment, known as "elite controllers" or "elite suppressors". They represent approximately 1 in 300 infected persons.

ACQUIRED IMMUNODEFICIENCY SYNDROME

Main symptoms of AIDS.

Acquired immunodeficiency syndrome (AIDS) is defined in terms of either a CD4+ T cell count below 200 cells per µL or the occurrence of specific diseases in association with an HIV
HIV
infection. In the absence of specific treatment, around half of people infected with HIV develop AIDS within ten years. The most common initial conditions that alert to the presence of AIDS are pneumocystis pneumonia (40%), cachexia in the form of HIV
HIV
wasting syndrome (20%), and esophageal candidiasis . Other common signs include recurring respiratory tract infections .

Opportunistic infections may be caused by bacteria , viruses , fungi , and parasites that are normally controlled by the immune system. Which infections occur depends partly on what organisms are common in the person's environment. These infections may affect nearly every organ system .

People with AIDS have an increased risk of developing various viral-induced cancers, including Kaposi\'s sarcoma , Burkitt\'s lymphoma , primary central nervous system lymphoma , and cervical cancer . Kaposi's sarcoma is the most common cancer occurring in 10 to 20% of people with HIV. The second most common cancer is lymphoma, which is the cause of death of nearly 16% of people with AIDS and is the initial sign of AIDS in 3 to 4%. Both these cancers are associated with human herpesvirus 8 . Cervical cancer occurs more frequently in those with AIDS because of its association with human papillomavirus (HPV). Conjunctival cancer (of the layer that lines the inner part of eyelids and the white part of the eye) is also more common in those with HIV.

Additionally, people with AIDS frequently have systemic symptoms such as prolonged fevers, sweats (particularly at night), swollen lymph nodes, chills, weakness, and unintended weight loss . Diarrhea is another common symptom, present in about 90% of people with AIDS. They can also be affected by diverse psychiatric and neurological symptoms independent of opportunistic infections and cancers.

TRANSMISSION

Average per act risk of getting HIV by exposure route to an infected source EXPOSURE ROUTE CHANCE OF INFECTION

BLOOD TRANSFUSION 90%

CHILDBIRTH (TO CHILD) 25%

NEEDLE-SHARING INJECTION DRUG USE 0.67%

PERCUTANEOUS NEEDLE STICK 0.30%

RECEPTIVE ANAL INTERCOURSE* 0.04–3.0%

INSERTIVE ANAL INTERCOURSE* 0.03%

RECEPTIVE PENILE-VAGINAL INTERCOURSE* 0.05–0.30%

INSERTIVE PENILE-VAGINAL INTERCOURSE* 0.01–0.38%

RECEPTIVE ORAL INTERCOURSE*§ 0–0.04%

INSERTIVE ORAL INTERCOURSE*§ 0–0.005%

* assuming no condom use § source refers to oral intercourse performed on a man

HIV
HIV
is transmitted by three main routes: sexual contact , significant exposure to infected body fluids or tissues, and from mother to child during pregnancy, delivery, or breastfeeding (known as vertical transmission ). There is no risk of acquiring HIV
HIV
if exposed to feces , nasal secretions, saliva, sputum , sweat, tears, urine, or vomit unless these are contaminated with blood. It is possible to be co-infected by more than one strain of HIV—a condition known as HIV superinfection .

SEXUAL

The most frequent mode of transmission of HIV
HIV
is through sexual contact with an infected person. Globally, the most common mode of HIV
HIV
transmission is via sexual contacts between people of the opposite sex ; however, the pattern of transmission varies among countries. As of 2014, most HIV
HIV
transmission in the United States occurred among men who had sex with men (83% of new HIV
HIV
diagnoses among males aged 13 and older and 67% of total new diagnoses). In the US, gay and bisexual men aged 13 to 24 accounted for an estimated 92% of new HIV
HIV
diagnoses among all men in their age group and 27% of new diagnoses among all gay and bisexual men. About 15% of gay and bisexual men have HIV while 28 percent of transgender women test positive in the US.

With regard to unprotected heterosexual contacts, estimates of the risk of HIV
HIV
transmission per sexual act appear to be four to ten times higher in low-income countries than in high-income countries. In low-income countries, the risk of female-to-male transmission is estimated as 0.38% per act, and of male-to-female transmission as 0.30% per act; the equivalent estimates for high-income countries are 0.04% per act for female-to-male transmission, and 0.08% per act for male-to-female transmission. The risk of transmission from anal intercourse is especially high, estimated as 1.4–1.7% per act in both heterosexual and homosexual contacts. While the risk of transmission from oral sex is relatively low, it is still present. The risk from receiving oral sex has been described as "nearly nil"; however, a few cases have been reported. The per-act risk is estimated at 0–0.04% for receptive oral intercourse. In settings involving prostitution in low income countries, risk of female-to-male transmission has been estimated as 2.4% per act and male-to-female transmission as 0.05% per act.

Risk of transmission increases in the presence of many sexually transmitted infections and genital ulcers . Genital ulcers appear to increase the risk approximately fivefold. Other sexually transmitted infections, such as gonorrhea , chlamydia , trichomoniasis , and bacterial vaginosis , are associated with somewhat smaller increases in risk of transmission.

The viral load of an infected person is an important risk factor in both sexual and mother-to-child transmission. During the first 2.5 months of an HIV
HIV
infection a person's infectiousness is twelve times higher due to this high viral load. If the person is in the late stages of infection, rates of transmission are approximately eightfold greater.

Commercial sex workers (including those in pornography ) have an increased rate of HIV. Rough sex can be a factor associated with an increased risk of transmission. Sexual assault is also believed to carry an increased risk of HIV
HIV
transmission as condoms are rarely worn, physical trauma to the vagina or rectum is likely, and there may be a greater risk of concurrent sexually transmitted infections.

BODY FLUIDS

CDC poster from 1989 highlighting the threat of AIDS associated with drug use

The second most frequent mode of HIV
HIV
transmission is via blood and blood products. Blood-borne transmission can be through needle-sharing during intravenous drug use, needle stick injury, transfusion of contaminated blood or blood product, or medical injections with unsterilized equipment. The risk from sharing a needle during drug injection is between 0.63 and 2.4% per act, with an average of 0.8%. The risk of acquiring HIV
HIV
from a needle stick from an HIV-infected person is estimated as 0.3% (about 1 in 333) per act and the risk following mucous membrane exposure to infected blood as 0.09% (about 1 in 1000) per act. In the United States intravenous drug users made up 12% of all new cases of HIV
HIV
in 2009, and in some areas more than 80% of people who inject drugs are HIV
HIV
positive.

HIV
HIV
is transmitted in about 93% of blood transfusions using infected blood. In developed countries the risk of acquiring HIV
HIV
from a blood transfusion is extremely low (less than one in half a million) where improved donor selection and HIV
HIV
screening is performed; for example, in the UK the risk is reported at one in five million and in the United States it was one in 1.5 million in 2008. In low income countries, only half of transfusions may be appropriately screened (as of 2008), and it is estimated that up to 15% of HIV
HIV
infections in these areas come from transfusion of infected blood and blood products, representing between 5% and 10% of global infections. Although rare because of screening , it is possible to acquire HIV from organ and tissue transplantation .

Unsafe medical injections play a significant role in HIV
HIV
spread in sub-Saharan Africa . In 2007, between 12 and 17% of infections in this region were attributed to medical syringe use. The World Health Organization estimates the risk of transmission as a result of a medical injection in Africa at 1.2%. Significant risks are also associated with invasive procedures, assisted delivery, and dental care in this area of the world.

People giving or receiving tattoos , piercings , and scarification are theoretically at risk of infection but no confirmed cases have been documented. It is not possible for mosquitoes or other insects to transmit HIV.

MOTHER-TO-CHILD

Main articles: HIV
HIV
and pregnancy and HIV
HIV
and breastfeeding

HIV
HIV
can be transmitted from mother to child during pregnancy, during delivery, or through breast milk, resulting in the baby also contracting HIV. This is the third most common way in which HIV
HIV
is transmitted globally. In the absence of treatment, the risk of transmission before or during birth is around 20% and in those who also breastfeed 35%. As of 2008, vertical transmission accounted for about 90% of cases of HIV
HIV
in children. With appropriate treatment the risk of mother-to-child infection can be reduced to about 1%. Preventive treatment involves the mother taking antiretrovirals during pregnancy and delivery, an elective caesarean section , avoiding breastfeeding, and administering antiretroviral drugs to the newborn. Antiretrovirals when taken by either the mother or the infant decrease the risk of transmission in those who do breastfeed. However, many of these measures are not available in the developing world. If blood contaminates food during pre-chewing it may pose a risk of transmission.

If a woman is untreated, two years of breastfeeding results in an HIV/AIDS
HIV/AIDS
risk in her baby of about 17%. Treatment decreases this risk to 1 to 2% per year. Due to the increased risk of death without breastfeeding in many areas in the developing world, the World Health Organization recommends either: (1) the mother and baby being treated with antiretroviral medication while breastfeeding being continued (2) the provision of safe formula.

VIROLOGY

Main article: HIV
HIV
Diagram of a HIV
HIV
virion structure Scanning electron micrograph of HIV-1, colored green, budding from a cultured lymphocyte .

HIV
HIV
is the cause of the spectrum of disease known as HIV/AIDS. HIV
HIV
is a retrovirus that primarily infects components of the human immune system such as CD4+ T cells, macrophages and dendritic cells . It directly and indirectly destroys CD4+ T cells.

HIV
HIV
is a member of the genus Lentivirus , part of the family Retroviridae . Lentiviruses share many morphological and biological characteristics. Many species of mammals are infected by lentiviruses, which are characteristically responsible for long-duration illnesses with a long incubation period . Lentiviruses are transmitted as single-stranded, positive-sense , enveloped RNA
RNA
viruses . Upon entry into the target cell, the viral RNA
RNA
genome is converted (reverse transcribed) into double-stranded DNA
DNA
by a virally encoded reverse transcriptase that is transported along with the viral genome in the virus particle. The resulting viral DNA
DNA
is then imported into the cell nucleus and integrated into the cellular DNA
DNA
by a virally encoded integrase and host co-factors. Once integrated, the virus may become latent , allowing the virus and its host cell to avoid detection by the immune system. Alternatively, the virus may be transcribed , producing new RNA
RNA
genomes and viral proteins that are packaged and released from the cell as new virus particles that begin the replication cycle anew.

HIV
HIV
is now known to spread between CD4+ T cells by two parallel routes: cell-free spread and cell-to-cell spread, i.e. it employs hybrid spreading mechanisms. In the cell-free spread, virus particles bud from an infected T cell, enter the blood/extracellular fluid and then infect another T cell following a chance encounter. HIV
HIV
can also disseminate by direct transmission from one cell to another by a process of cell-to-cell spread. The hybrid spreading mechanisms of HIV
HIV
contribute to the virus's ongoing replication against antiretroviral therapies.

Two types of HIV
HIV
have been characterized: HIV-1 and HIV-2. HIV-1 is the virus that was originally discovered (and initially referred to also as LAV or HTLV-III). It is more virulent , more infective , and is the cause of the majority of HIV
HIV
infections globally. The lower infectivity of HIV-2
HIV-2
as compared with HIV-1 implies that fewer people exposed to HIV-2
HIV-2
will be infected per exposure. Because of its relatively poor capacity for transmission, HIV-2
HIV-2
is largely confined to West Africa .

PATHOPHYSIOLOGY

Main article: Pathophysiology of HIV/AIDS Play media HIV/AIDS explained in a simple way HIV
HIV
replication cycle

After the virus enters the body there is a period of rapid viral replication , leading to an abundance of virus in the peripheral blood. During primary infection, the level of HIV
HIV
may reach several million virus particles per milliliter of blood. This response is accompanied by a marked drop in the number of circulating CD4+ T cells. The acute viremia is almost invariably associated with activation of CD8+ T cells , which kill HIV-infected cells, and subsequently with antibody production, or seroconversion . The CD8+ T cell response is thought to be important in controlling virus levels, which peak and then decline, as the CD4+ T cell counts recover. A good CD8+ T cell response has been linked to slower disease progression and a better prognosis, though it does not eliminate the virus.

Ultimately, HIV
HIV
causes AIDS by depleting CD4+ T cells . This weakens the immune system and allows opportunistic infections . T cells are essential to the immune response and without them, the body cannot fight infections or kill cancerous cells. The mechanism of CD4+ T cell depletion differs in the acute and chronic phases. During the acute phase, HIV-induced cell lysis and killing of infected cells by cytotoxic T cells accounts for CD4+ T cell depletion, although apoptosis may also be a factor. During the chronic phase, the consequences of generalized immune activation coupled with the gradual loss of the ability of the immune system to generate new T cells appear to account for the slow decline in CD4+ T cell numbers.

Although the symptoms of immune deficiency characteristic of AIDS do not appear for years after a person is infected, the bulk of CD4+ T cell loss occurs during the first weeks of infection, especially in the intestinal mucosa, which harbors the majority of the lymphocytes found in the body. The reason for the preferential loss of mucosal CD4+ T cells is that the majority of mucosal CD4+ T cells express the CCR5 protein which HIV
HIV
uses as a co-receptor to gain access to the cells, whereas only a small fraction of CD4+ T cells in the bloodstream do so. A specific genetic change that alters the CCR5 protein when present in both chromosomes very effectively prevents HIV-1 infection.

HIV
HIV
seeks out and destroys CCR5 expressing CD4+ T cells during acute infection. A vigorous immune response eventually controls the infection and initiates the clinically latent phase. CD4+ T cells in mucosal tissues remain particularly affected. Continuous HIV replication causes a state of generalized immune activation persisting throughout the chronic phase. Immune activation, which is reflected by the increased activation state of immune cells and release of pro-inflammatory cytokines , results from the activity of several HIV gene products and the immune response to ongoing HIV
HIV
replication. It is also linked to the breakdown of the immune surveillance system of the gastrointestinal mucosal barrier caused by the depletion of mucosal CD4+ T cells during the acute phase of disease.

DIAGNOSIS

Main article: Diagnosis of HIV/AIDS
Diagnosis of HIV/AIDS
A generalized graph of the relationship between HIV
HIV
copies (viral load) and CD4+ T cell counts over the average course of untreated HIV
HIV
infection. CD4+ T Lymphocyte
Lymphocyte
count (cells/mm³) HIV
HIV
RNA
RNA
copies per mL of plasma

HIV/AIDS
HIV/AIDS
is diagnosed via laboratory testing and then staged based on the presence of certain signs or symptoms . HIV
HIV
screening is recommended by the United States Preventive Services Task Force for all people 15 years to 65 years of age including all pregnant women. Additionally, testing is recommended for those at high risk, which includes anyone diagnosed with a sexually transmitted illness. In many areas of the world, a third of HIV
HIV
carriers only discover they are infected at an advanced stage of the disease when AIDS or severe immunodeficiency has become apparent.

HIV
HIV
TESTING

Most people infected with HIV
HIV
develop specific antibodies (i.e. seroconvert ) within three to twelve weeks of the initial infection. Diagnosis of primary HIV
HIV
before seroconversion is done by measuring HIV- RNA
RNA
or p24 antigen . Positive results obtained by antibody or PCR testing are confirmed either by a different antibody or by PCR.

Antibody tests in children younger than 18 months are typically inaccurate due to the continued presence of maternal antibodies . Thus HIV
HIV
infection can only be diagnosed by PCR testing for HIV
HIV
RNA
RNA
or DNA, or via testing for the p24 antigen. Much of the world lacks access to reliable PCR testing and many places simply wait until either symptoms develop or the child is old enough for accurate antibody testing. In sub-Saharan Africa as of 2007–2009 between 30 and 70% of the population were aware of their HIV
HIV
status. In 2009, between 3.6 and 42% of men and women in Sub-Saharan countries were tested which represented a significant increase compared to previous years.

CLASSIFICATIONS

Two main clinical staging systems are used to classify HIV
HIV
and HIV-related disease for surveillance purposes: the WHO
WHO
disease staging system for HIV
HIV
infection and disease , and the CDC classification system for HIV
HIV
infection . The CDC's classification system is more frequently adopted in developed countries. Since the WHO's staging system does not require laboratory tests, it is suited to the resource-restricted conditions encountered in developing countries, where it can also be used to help guide clinical management. Despite their differences, the two systems allow comparison for statistical purposes.

The World Health Organization first proposed a definition for AIDS in 1986. Since then, the WHO
WHO
classification has been updated and expanded several times, with the most recent version being published in 2007. The WHO
WHO
system uses the following categories:

* Primary HIV
HIV
infection: May be either asymptomatic or associated with acute retroviral syndrome. * Stage I: HIV
HIV
infection is asymptomatic with a CD4+ T cell count (also known as CD4 count) greater than 500 per microlitre (µl or cubic mm) of blood. May include generalized lymph node enlargement. * Stage II: Mild symptoms which may include minor mucocutaneous manifestations and recurrent upper respiratory tract infections . A CD4 count of less than 500/µl. * Stage III: Advanced symptoms which may include unexplained chronic diarrhea for longer than a month, severe bacterial infections including tuberculosis of the lung, and a CD4 count of less than 350/µl. * Stage IV or AIDS: severe symptoms which include toxoplasmosis of the brain, candidiasis of the esophagus , trachea , bronchi or lungs and Kaposi\'s sarcoma . A CD4 count of less than 200/µl.

The United States Center for Disease Control and Prevention also created a classification system for HIV, and updated it in 2008 and 2014. This system classifies HIV
HIV
infections based on CD4 count and clinical symptoms, and describes the infection in five groups. In those greater than six years of age it is:

* Stage 0: the time between a negative or indeterminate HIV
HIV
test followed less than 180 days by a positive test * Stage 1: CD4 count ≥ 500 cells/µl and no AIDS defining conditions * Stage 2: CD4 count 200 to 500 cells/µl and no AIDS defining conditions * Stage 3: CD4 count ≤ 200 cells/µl or AIDS defining conditions * Unknown: if insufficient information is available to make any of the above classifications

For surveillance purposes, the AIDS diagnosis still stands even if, after treatment, the CD4+ T cell count rises to above 200 per µL of blood or other AIDS-defining illnesses are cured.

PREVENTION

Main article: Prevention of HIV/AIDS
Prevention of HIV/AIDS
AIDS Clinic, McLeod Ganj
McLeod Ganj
, Himachal Pradesh, India, 2010

SEXUAL CONTACT

Consistent condom use reduces the risk of HIV
HIV
transmission by approximately 80% over the long term. When condoms are used consistently by a couple in which one person is infected, the rate of HIV
HIV
infection is less than 1% per year. There is some evidence to suggest that female condoms may provide an equivalent level of protection. Application of a vaginal gel containing tenofovir (a reverse transcriptase inhibitor ) immediately before sex seems to reduce infection rates by approximately 40% among African women. By contrast, use of the spermicide nonoxynol-9 may increase the risk of transmission due to its tendency to cause vaginal and rectal irritation.

Circumcision in Sub-Saharan Africa "reduces the acquisition of HIV
HIV
by heterosexual men by between 38% and 66% over 24 months". Due to these studies, both the World Health Organization and UNAIDS recommended male circumcision as a method of preventing female-to-male HIV transmission in 2007 in areas with a high rates of HIV. However, whether it protects against male-to-female transmission is disputed, and whether it is of benefit in developed countries and among men who have sex with men is undetermined. The International Antiviral Society, however, does recommend for all sexually active heterosexual males and that it be discussed as an option with men who have sex with men. Some experts fear that a lower perception of vulnerability among circumcised men may cause more sexual risk-taking behavior, thus negating its preventive effects.

Programs encouraging sexual abstinence do not appear to affect subsequent HIV
HIV
risk. Evidence of any benefit from peer education is equally poor. Comprehensive sexual education provided at school may decrease high risk behavior. A substantial minority of young people continues to engage in high-risk practices despite knowing about HIV/AIDS, underestimating their own risk of becoming infected with HIV. Voluntary counseling and testing people for HIV
HIV
does not affect risky behavior in those who test negative but does increase condom use in those who test positive. It is not known whether treating other sexually transmitted infections is effective in preventing HIV.

PRE-EXPOSURE

Antiretroviral treatment among people with HIV
HIV
whose CD4 count ≤ 550 cells/µL is a very effective way to prevent HIV
HIV
infection of their partner (a strategy known as treatment as prevention, or TASP). TASP is associated with a 10 to 20 fold reduction in transmission risk. Pre-exposure prophylaxis (PrEP) with a daily dose of the medications tenofovir , with or without emtricitabine , is effective in a number of groups including men who have sex with men, couples where one is HIV
HIV
positive, and young heterosexuals in Africa. It may also be effective in intravenous drug users with a study finding a decrease in risk of 0.7 to 0.4 per 100 person years.

Universal precautions within the health care environment are believed to be effective in decreasing the risk of HIV. Intravenous drug use is an important risk factor and harm reduction strategies such as needle-exchange programs and opioid substitution therapy appear effective in decreasing this risk.

POST-EXPOSURE

A course of antiretrovirals administered within 48 to 72 hours after exposure to HIV-positive blood or genital secretions is referred to as post-exposure prophylaxis (PEP). The use of the single agent zidovudine reduces the risk of a HIV
HIV
infection five-fold following a needle-stick injury. As of 2013, the prevention regimen recommended in the United States consists of three medications—tenofovir , emtricitabine and raltegravir —as this may reduce the risk further.

PEP treatment is recommended after a sexual assault when the perpetrator is known to be HIV
HIV
positive, but is controversial when their HIV
HIV
status is unknown. The duration of treatment is usually four weeks and is frequently associated with adverse effects—where zidovudine is used, about 70% of cases result in adverse effects such as nausea (24%), fatigue (22%), emotional distress (13%) and headaches (9%).

MOTHER-TO-CHILD

Main article: HIV
HIV
and pregnancy

Programs to prevent the vertical transmission of HIV
HIV
(from mothers to children) can reduce rates of transmission by 92–99%. This primarily involves the use of a combination of antiviral medications during pregnancy and after birth in the infant and potentially includes bottle feeding rather than breastfeeding . If replacement feeding is acceptable, feasible, affordable, sustainable, and safe, mothers should avoid breastfeeding their infants; however exclusive breastfeeding is recommended during the first months of life if this is not the case. If exclusive breastfeeding is carried out, the provision of extended antiretroviral prophylaxis to the infant decreases the risk of transmission. In 2015, Cuba
Cuba
became the first country in the world to eradicate mother-to-child transmission of HIV.

VACCINATION

Main article: HIV
HIV
vaccine

Currently, there is no licensed vaccine for HIV
HIV
or AIDS. The most effective vaccine trial to date, RV 144 , was published in 2009 and found a partial reduction in the risk of transmission of roughly 30%, stimulating some hope in the research community of developing a truly effective vaccine. Further trials of the RV 144 vaccine are ongoing.

TREATMENT

Main article: Management of HIV/AIDS
Management of HIV/AIDS

There is currently no cure or effective HIV
HIV
vaccine . Treatment consists of highly active antiretroviral therapy (HAART) which slows progression of the disease. As of 2010 more than 6.6 million people were taking them in low and middle income countries. Treatment also includes preventive and active treatment of opportunistic infections.

ANTIVIRAL THERAPY

Stribild – a common once-daily ART regime consisting of elvitegravir , emtricitabine , tenofovir and the booster cobicistat

Current HAART options are combinations (or "cocktails") consisting of at least three medications belonging to at least two types, or "classes," of antiretroviral agents. Initially treatment is typically a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside analog reverse transcriptase inhibitors (NRTIs). Typical NRTIs include: zidovudine (AZT) or tenofovir (TDF) and lamivudine (3TC) or emtricitabine (FTC). Combinations of agents which include protease inhibitors (PI) are used if the above regimen loses effectiveness.

The World Health Organization and United States recommends antiretrovirals in people of all ages including pregnant women as soon as the diagnosis is made regardless of CD4 count. Once treatment is begun it is recommended that it is continued without breaks or "holidays". Many people are diagnosed only after treatment ideally should have begun. The desired outcome of treatment is a long term plasma HIV- RNA
RNA
count below 50 copies/mL. Levels to determine if treatment is effective are initially recommended after four weeks and once levels fall below 50 copies/mL checks every three to six months are typically adequate. Inadequate control is deemed to be greater than 400 copies/mL. Based on these criteria treatment is effective in more than 95% of people during the first year.

Benefits of treatment include a decreased risk of progression to AIDS and a decreased risk of death. In the developing world treatment also improves physical and mental health. With treatment there is a 70% reduced risk of acquiring tuberculosis. Additional benefits include a decreased risk of transmission of the disease to sexual partners and a decrease in mother-to-child transmission. The effectiveness of treatment depends to a large part on compliance. Reasons for non-adherence include poor access to medical care, inadequate social supports, mental illness and drug abuse . The complexity of treatment regimens (due to pill numbers and dosing frequency) and adverse effects may reduce adherence. Even though cost is an important issue with some medications, 47% of those who needed them were taking them in low and middle income countries as of 2010 and the rate of adherence is similar in low-income and high-income countries.

Specific adverse events are related to the antiretroviral agent taken. Some relatively common adverse events include: lipodystrophy syndrome , dyslipidemia , and diabetes mellitus , especially with protease inhibitors. Other common symptoms include diarrhea , and an increased risk of cardiovascular disease . Newer recommended treatments are associated with fewer adverse effects. Certain medications may be associated with birth defects and therefore may be unsuitable for women hoping to have children.

Treatment recommendations for children are somewhat different from those for adults. The World Health Organization recommends treating all children less than 5 years of age; children above 5 are treated like adults. The United States guidelines recommend treating all children less than 12 months of age and all those with HIV
HIV
RNA
RNA
counts greater than 100,000 copies/mL between one year and five years of age.

OPPORTUNISTIC INFECTIONS

Measures to prevent opportunistic infections are effective in many people with HIV/AIDS. In addition to improving current disease, treatment with antiretrovirals reduces the risk of developing additional opportunistic infections. Adults and adolescents who are living with HIV
HIV
(even on anti-retroviral therapy) with no evidence of active tuberculosis in settings with high tuberculosis burden should receive isoniazid preventive therapy (IPT), the tuberculin skin test can be used to help decide if IPT is needed. Vaccination
Vaccination
against hepatitis A and B is advised for all people at risk of HIV
HIV
before they become infected; however it may also be given after infection. Trimethoprim/sulfamethoxazole prophylaxis between four and six weeks of age and ceasing breastfeeding in infants born to HIV
HIV
positive mothers is recommended in resource limited settings. It is also recommended to prevent PCP when a person's CD4 count is below 200 cells/uL and in those who have or have previously had PCP. People with substantial immunosuppression are also advised to receive prophylactic therapy for toxoplasmosis and MAC . Appropriate preventive measures have reduced the rate of these infections by 50% between 1992 and 1997. Influenza vaccination and pneumococcal polysaccharide vaccine are often recommended in people with HIV/AIDS with some evidence of benefit.

DIET

Main article: Nutrition and HIV/AIDS
Nutrition and HIV/AIDS

The World Health Organization (WHO) has issued recommendations regarding nutrient requirements in HIV/AIDS. A generally healthy diet is promoted. Dietary intake of micronutrients at RDA levels by HIV-infected adults is recommended by the WHO; higher intake of vitamin A, zinc , and iron can produce adverse effects in HIV
HIV
positive adults, and is not recommended unless there is documented deficiency. Dietary supplementation for people who are infected with HIV
HIV
and who have inadequate nutrition or dietary deficiencies may strengthen their immune systems or help them recover from infections, however evidence indicating an overall benefit in morbidity or reduction in mortality is not consistent.

Evidence for supplementation with selenium is mixed with some tentative evidence of benefit. For pregnant and lactating women with HIV, multivitamin supplement improves outcomes for both mothers and children. If the pregnant or lactating mother has been advised to take anti-retroviral medication to prevent mother-to-child HIV transmission, multivitamin supplements should not replace these treatments. There is some evidence that vitamin A supplementation in children with an HIV
HIV
infection reduces mortality and improves growth.

ALTERNATIVE MEDICINE

In the US, approximately 60% of people with HIV
HIV
use various forms of complementary or alternative medicine , even though the effectiveness of most of these therapies has not been established. There is not enough evidence to support the use of herbal medicines . There is insufficient evidence to recommend or support the use of medical cannabis to try to increase appetite or weight gain.

PROGNOSIS

Deaths due to HIV/AIDS
HIV/AIDS
per million persons in 2012 0 1–4 5–12 13–34 35–61 62–134 135–215 216–458 459-1,402 1,403–5,828

HIV/AIDS
HIV/AIDS
has become a chronic rather than an acutely fatal disease in many areas of the world. Prognosis varies between people, and both the CD4 count and viral load are useful for predicted outcomes. Without treatment, average survival time after infection with HIV
HIV
is estimated to be 9 to 11 years, depending on the HIV
HIV
subtype. After the diagnosis of AIDS, if treatment is not available, survival ranges between 6 and 19 months. HAART and appropriate prevention of opportunistic infections reduces the death rate by 80%, and raises the life expectancy for a newly diagnosed young adult to 20–50 years. This is between two thirds and nearly that of the general population. If treatment is started late in the infection, prognosis is not as good: for example, if treatment is begun following the diagnosis of AIDS, life expectancy is ~10–40 years. Half of infants born with HIV
HIV
die before two years of age without treatment. Disability-adjusted life year for HIV
HIV
and AIDS per 100,000 inhabitants as of 2004.

no data ≤ 10 10–25 25–50 50–100 100–500 500–1000 1000–2500 2500–5000 5000–7500

7500-10000 10000-50000 ≥ 50000

The primary causes of death from HIV/AIDS
HIV/AIDS
are opportunistic infections and cancer , both of which are frequently the result of the progressive failure of the immune system. Risk of cancer appears to increase once the CD4 count is below 500/μL. The rate of clinical disease progression varies widely between individuals and has been shown to be affected by a number of factors such as a person's susceptibility and immune function; their access to health care, the presence of co-infections; and the particular strain (or strains) of the virus involved.

Tuberculosis
Tuberculosis
co-infection is one of the leading causes of sickness and death in those with HIV/AIDS
HIV/AIDS
being present in a third of all HIV-infected people and causing 25% of HIV-related deaths. HIV
HIV
is also one of the most important risk factors for tuberculosis. Hepatitis
Hepatitis
C is another very common co-infection where each disease increases the progression of the other. The two most common cancers associated with HIV/AIDS
HIV/AIDS
are Kaposi\'s sarcoma and AIDS-related non-Hodgkin\'s lymphoma . Other cancers that are more frequent include anal cancer , Burkitt\'s lymphoma , primary central nervous system lymphoma , and cervical cancer .

Even with anti-retroviral treatment, over the long term HIV-infected people may experience neurocognitive disorders , osteoporosis , neuropathy , cancers, nephropathy , and cardiovascular disease . Some conditions like lipodystrophy may be caused both by HIV
HIV
and its treatment.

EPIDEMIOLOGY

Main article: Epidemiology of HIV/AIDS Estimated percentage of HIV
HIV
among young adults (15–49) per country as of 2011.

No data

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