HIV/AIDS
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 developing common infections such as 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 unintended weight loss.
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 and it
resulted in 1 million deaths. There were 300,000 fewer new HIV cases in
2016 than in 2015. Most of those infected live in sub-Saharan Africa. From
the time AIDS was identified in the early 1980s to 2017, the disease has caused
an estimated 35 million deaths worldwide. HIV/AIDS is considered
a pandemic—a disease outbreak which is present
over a large area and is actively spreading. HIV 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 infection—was identified in the early part of the decade.
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 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.
Signs and
symptoms
Main
article: Signs and symptoms of HIV/AIDS
There are three main stages of HIV infection: acute infection,
clinical latency and AIDS.
Acute infection
The initial period following the contraction of HIV is called
acute HIV, primary HIV or acute retroviral syndrome. Many individuals
develop an influenza-like illness or a mononucleosis-like illness 2–4 weeks
after 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, tiredness,
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 neuropathyor 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 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 be considered in people presenting
with 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 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 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
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 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 wasting syndrome (20%), and esophageal candidiasis. Other common signs
include recurrent 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(HHV-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 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 if exposed to feces, nasal secretions,
saliva, sputum,
sweat, tears, urine, or vomit unless these are contaminated with blood. It
is also 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 is through sexual
contact with an infected person. Globally, the most common mode of 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
transmission in the United States occurred among men who had sex with men (83% of new
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 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% of transgender women test positive in the US.
With regard to unprotected heterosexual
contacts, estimates of the risk of 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 infection a person's infectiousness is twelve times
higher due to the high viral load associated with acute HIV. If the person
is in the late stages of infection, rates of transmission are approximately
eightfold greater. An HIV-positive person who has an undetectable viral
load as a result of long-term treatment has effectively no risk of transmitting
HIV sexually.
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 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
The second most frequent mode of 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 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 in 2009, and in
some areas more than 80% of people who inject drugs are HIV positive.
HIV is transmitted in about 93% of blood
transfusions using infected blood. In developed countries
the risk of acquiring HIV from a blood transfusion is extremely low (less than
one in half a million) where improved donor selection and 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 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 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 and pregnancy and HIV and breastfeeding
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 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 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 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. Infection
with HIV during pregnancy is also associated with miscarriage.
Virology
HIV is
the cause of the spectrum of disease known as HIV/AIDS. 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 is a member of the genus Lentivirus, part
of the family Retroviridae. Lentiviruses share many morphological and biologicalcharacteristics.
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 viruses.
Upon entry into the target cell, the viral RNA genome is
converted (reverse transcribed) into double-stranded DNA by a virally
encoded reverse transcriptase that is transported
along with the viral genome in the virus particle. The resulting viral DNA is
then imported into the cell nucleus and integrated into the cellular 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 genomes and
viral proteins that are packaged and released from the cell as new virus
particles that begin the replication cycle anew.
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 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 contribute to
the virus's ongoing replication against antiretroviral therapies.
Two types of 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
infections globally. The lower infectivity of HIV-2 as compared with HIV-1
implies that fewer people exposed to HIV-2 will be infected per exposure.
Because of its relatively poor capacity for transmission, HIV-2 is largely
confined to West Africa.
Pathophysiology
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 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 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 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 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 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
CD4+ T
Lymphocyte count (cells/mm³)
HIV RNA copies per mL of
plasma
|
Blood test
|
Days
|
|
Antibody
test (rapid test, ELISA 3rd gen)
|
23–90
|
|
Antibody and
p24 antigen test (ELISA 4th gen)
|
18–45
|
|
PCR
|
10–33
|
HIV/AIDS is diagnosed via laboratory testing and then staged
based on the presence of certain signs or symptoms. 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 carriers only discover
they are infected at an advanced stage of the disease when AIDS or severe
immunodeficiency has become apparent.
HIV testing
Most people infected with HIV develop specific antibodies (i.e. seroconvert)
within three to twelve weeks after the initial infection. Diagnosis of
primary HIV before seroconversion is done by measuring HIV-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
infection can only be diagnosed by PCR testing for HIV 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 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 and
HIV-related disease for surveillance purposes: the WHO disease
staging system for HIV infection and disease, and the CDC classification system for 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 classification has been updated and
expanded several times, with the most recent version being published in 2007. The
WHO system uses the following categories:
·
Primary HIV infection: May be either asymptomatic or associated
with acute retroviral syndrome.
· Stage I: 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 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 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.[2]
Prevention
Main
article: Prevention of HIV/AIDS
Sexual contact
Consistent condom use reduces the risk of 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 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 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 in 2007 as a method of preventing female-to-male HIV
transmission in areas with 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 it 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 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 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 whose CD4 count ≤
550 cells/µL is a very effective way to prevent 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 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 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 positive, but is controversial when their
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 and pregnancy
Programs to prevent the vertical transmission of 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, Cubabecame the first
country in the world to eradicate mother-to-child transmission of HIV.
Vaccination
Main
article: HIV vaccine
Currently, there is no licensed vaccine for
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
There is currently no cure or effective 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
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 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 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 (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 against hepatitisA
and B is advised for all people at risk of 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 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
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 positive adults, and is not recommended unless there is
documented deficiency. Dietary supplementation for people who are infected
with 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
infection reduces mortality and improves growth.
Alternative medicine
In the US, approximately 60% of people with 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 cannabisto
try to increase appetite or weight gain.
Prognosis
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 is estimated to be 9
to 11 years, depending on the 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
die before two years of age without treatment.
The primary causes of death from 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 co-infection is one of the leading causes of
sickness and death in those with HIV/AIDS being present in a third of all
HIV-infected people and causing 25% of HIV-related deaths. HIV is also one
of the most important risk factors for tuberculosis. 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 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 experienceneurocognitive disorders, osteoporosis, neuropathy, cancers, nephropathy, and cardiovascular disease. Some conditions,
such as lipodystrophy, may be caused both by HIV and its treatment.
Epidemiology
Main
article: Epidemiology of HIV/AIDS
HIV/AIDS is a global pandemic. As of 2016, approximately 36.7 million people have HIV worldwide with the number of new infections that year being about 1.8 million. This is down from 3.1 million new infections in 2001. Slightly over half the infected population are women and 2.1 million are children. It resulted in about 1 million deaths in 2016, down from a peak of 1.9 million in 2005.
Sub-Saharan Africa is the region most
affected. In 2010, an estimated 68% (22.9 million) of all HIV cases and
66% of all deaths (1.2 million) occurred in this region. This means
that about 5% of the adult population is infected and it is believed to be
the cause of 10% of all deaths in children. Here in contrast to other
regions women compose nearly 60% of cases. South Africa has
the largest population of people with HIV of any country in the world at
5.9 million. Life expectancy has fallen in the
worst-affected countries due to HIV/AIDS; for example, in 2006 it was estimated
that it had dropped from 65 to 35 years in Botswana. Mother-to-child
transmission, as of 2013, in Botswana and South Africa has decreased to less
than 5% with improvement in many other African nations due to improved access
to antiretroviral therapy.
South & South East Asia is the second
most affected; in 2010 this region contained an estimated 4 million cases
or 12% of all people living with HIV resulting in approximately 250,000 deaths. Approximately
2.4 million of these cases are in India.
In 2008 in the United States approximately 1.2 million
people were living with HIV, resulting in about 17,500 deaths. The US Centers
for Disease Control and Prevention estimated that in 2008 20% of infected
Americans were unaware of their infection. As of 2016 about 675,000 people
have died of HIV/AIDS in the USA since the beginning of the HIV epidemic. In
the United Kingdom as of 2015 there were
approximately 101,200 cases which resulted in 594 deaths. In Canada as of
2008 there were about 65,000 cases causing 53 deaths. Between the first
recognition of AIDS in 1981 and 2009 it has led to nearly 30 million
deaths. Prevalence is lowest in Middle East and North Africa at 0.1% or
less, East Asia at
0.1% and Western and Central Europe at 0.2%. The worst affected European
countries, in 2009 and 2012 estimates, are Russia, Ukraine, Latvia, Moldova, Portugal and Belarus,
in decreasing order of prevalence.
History
Main
article: History of HIV/AIDS
Discovery
AIDS was first clinically observed in 1981 in the United States. The
initial cases were a cluster of injecting drug users and homosexual men with no
known cause of impaired immunity who showed symptoms of Pneumocystis carinii pneumonia (PCP),
a rare opportunistic infection that was known to occur in people with very
compromised immune systems. Soon thereafter, an unexpected number of
homosexual men developed a previously rare skin cancer called Kaposi's sarcoma (KS). Many
more cases of PCP and KS emerged, alerting U.S. Centers for Disease Control and
Prevention (CDC) and a CDC task force was formed to monitor the outbreak.
In the early days, the CDC did not have an official name for the
disease, often referring to it by way of the diseases that were associated with
it, for example, lymphadenopathy, the disease after which the
discoverers of HIV originally named the virus. They also used Kaposi's
sarcoma and opportunistic infections, the name by which a task force had
been set up in 1981. At one point, the CDC coined the phrase "the 4H
disease", since the syndrome seemed to affect heroin users,
homosexuals, hemophiliacs, and Haitians. In the
general press, the term "GRID", which stood for gay-related immune deficiency, had been
coined. However, after determining that AIDS was not isolated to the gay community, it
was realized that the term GRID was misleading and the term AIDS was introduced
at a meeting in July 1982. By September 1982 the CDC started referring to
the disease as AIDS.
In 1983, two separate research groups led by Robert Gallo and Luc Montagnier declared
that a novel retrovirus may have been infecting people with AIDS, and published
their findings in the same issue of the journal Science. Gallo
claimed that a virus his group had isolated from a person with AIDS was
strikingly similar in shape to
other human T-lymphotropic viruses (HTLVs)
his group had been the first to isolate. Gallo's group called their newly
isolated virus HTLV-III. At the same time, Montagnier's group isolated a virus
from a person presenting with swelling of the lymph nodes of
the neck and physical weakness, two characteristic symptoms of AIDS.
Contradicting the report from Gallo's group, Montagnier and his colleagues
showed that core proteins of this virus were immunologically different from
those of HTLV-I. Montagnier's group named their isolated virus
lymphadenopathy-associated virus (LAV). As these two viruses turned out to
be the same, in 1986, LAV and HTLV-III were renamed HIV.
Origins
Both HIV-1 and HIV-2 are believed to have originated in
non-human primates in
West-central Africa and were transferred to
humans in the early 20th century. HIV-1 appears to have
originated in southern Cameroon through the evolution of SIV(cpz), a simian immunodeficiency virus (SIV)
that infects wild chimpanzees (HIV-1 descends from the SIVcpz endemic in
the chimpanzee subspecies Pan troglodytes troglodytes). The
closest relative of HIV-2 is SIV(smm), a virus of the sooty mangabey (Cercocebus
atys atys), an Old World monkey living in coastal West Africa (from
southern Senegal to
western Côte d'Ivoire). New World
monkeys such as the owl monkey are
resistant to HIV-1 infection, possibly because of a
genomic fusionof two viral resistance genes. HIV-1 is thought to
have jumped the species barrier on at least three separate occasions, giving
rise to the three groups of the virus, M, N, and O.
There is evidence that humans who participate in bushmeat activities,
either as hunters or as bushmeat vendors, commonly acquire SIV. However,
SIV is a weak virus which is typically suppressed by the human immune system
within weeks of infection. It is thought that several transmissions of the
virus from individual to individual in quick succession are necessary to allow
it enough time to mutate into HIV. Furthermore, due to its relatively low
person-to-person transmission rate, SIV can only spread throughout the
population in the presence of one or more high-risk transmission channels,
which are thought to have been absent in Africa before the 20th century.
Specific proposed high-risk transmission channels, allowing the
virus to adapt to humans and spread throughout the society, depend on the
proposed timing of the animal-to-human crossing. Genetic studies of the virus
suggest that the most recent common ancestor of the HIV-1 M group dates back to
circa 1910. Proponents of this dating link the HIV epidemic with the
emergence of colonialism and growth of large colonial African cities,
leading to social changes, including a higher degree of sexual promiscuity, the
spread of prostitution, and the accompanying high frequency of genital ulcer diseases (such as syphilis)
in nascent colonial cities. While transmission rates of HIV during vaginal
intercourse are low under regular circumstances, they are increased many fold
if one of the partners suffers from a sexually transmitted infection causing
genital ulcers. Early 1900s colonial cities were notable due to their high
prevalence of prostitution and genital ulcers, to the degree that, as of 1928,
as many as 45% of female residents of eastern Kinshasawere
thought to have been prostitutes, and, as of 1933, around 15% of all residents
of the same city had syphilis.
An alternative view holds that unsafe medical practices in
Africa after World War II, such as unsterile reuse of single use syringes
during mass vaccination, antibiotic and anti-malaria treatment campaigns, were
the initial vector that allowed the virus to adapt to humans and spread.
The earliest well-documented case of HIV in a human dates back
to 1959 in the Congo. The earliest retrospectively
described case of AIDS is believed to have been in Norway beginning in 1966. In
July 1960, in the wake of Congo's independence, the United Nations recruited Francophone experts
and technicians from all over the world to assist in filling administrative
gaps left by Belgium, who did not leave behind an African elite to run the
country. By 1962, Haitians made up the second largest group of well-educated
experts (out of the 48 national groups recruited), that totaled around 4500 in
the country. Dr. Jacques Pépin, a Quebecer author
of The Origins of AIDS, stipulates that Haiti was one of HIV's
entry points to the United States and that one of them may have carried HIV
back across the Atlantic in the 1960s. Although the virus may have been
present in the United States as early as 1966, the vast majority of
infections occurring outside sub-Saharan Africa (including the U.S.) can be
traced back to a single unknown individual who became infected with HIV
in Haiti and
then brought the infection to the United States some time around 1969. The
epidemic then rapidly spread among high-risk groups (initially, sexually
promiscuous men who have sex with men). By 1978, the prevalence of HIV-1 among
homosexual male residents of New York City and San Francisco was
estimated at 5%, suggesting that several thousand individuals in the country
had been infected.
Society
and culture
Stigma
Main
article: Discrimination against people with
HIV/AIDS
Ryan White became
a poster child for
HIV after being expelled from school because he was infected.
AIDS stigma exists around the world in a variety of ways,
including ostracism, rejection,
discrimination and avoidance of HIV infected people; compulsory HIV testing
without prior consent or protection of confidentiality;
violence against HIV infected individuals or people who are perceived to be
infected with HIV; and the quarantine of
HIV infected individuals. Stigma-related violence or the fear of violence
prevents many people from seeking HIV testing, returning for their results, or
securing treatment, possibly turning what could be a manageable chronic illness
into a death sentence and perpetuating the spread of HIV.
AIDS stigma has been further divided into the following three
categories:
·
Instrumental AIDS stigma—a
reflection of the fear and apprehension that are likely to be associated with
any deadly and transmissible illness.
·
Symbolic AIDS stigma—the
use of HIV/AIDS to express attitudes toward the social groups or lifestyles
perceived to be associated with the disease.
·
Courtesy AIDS stigma—stigmatization
of people connected to the issue of HIV/AIDS or HIV-positive people.
Often, AIDS stigma is expressed in conjunction with one or more
other stigmas, particularly those associated with homosexuality, bisexuality, promiscuity,
prostitution, and intravenous drug use.
In many developed
countries, there is an association between AIDS and homosexuality or
bisexuality, and this association is correlated with higher levels
of sexual prejudice, such as anti-homosexual/bisexual attitudes. There
is also a perceived association between AIDS and all male-male sexual behavior,
including sex between uninfected men. However, the dominant mode of spread
worldwide for HIV remains heterosexual transmission.
In 2003, as part of an overall reform of marriage and population
legislation, it became legal for people with AIDS to marry in China.
In 2013 the U.S. National Library of Medicine developed
a traveling exhibition titled, "Surviving and Thriving: AIDS, Politics,
and Culture", covering medical research, U.S. government's response,
and personal stories from people with AIDS, caregivers, and activists.
Economic impact
Main
articles: Economic impact of HIV/AIDS and Cost of HIV treatment
HIV/AIDS affects the economics of both individuals and
countries. The gross domestic product of the most
affected countries has decreased due to the lack of human capital. Without
proper nutrition, health care and medicine, large numbers of people die from
AIDS-related complications. They will not only be unable to work, but will also
require significant medical care. It is estimated that as of 2007 there were
12 million AIDS orphans. Many are cared for by elderly grandparents.
Returning to work after beginning treatment for HIV/AIDS is
difficult, and affected people often work less than the average worker. Unemployment in
people with HIV/AIDS also is associated with suicidal
ideation, memory problems, and social isolation. Employment
increases self-esteem, sense of dignity, confidence, and quality of life for
people with HIV/AIDS. Anti-retroviral treatment may help people with HIV/AIDS
work more, and may increase the chance that a person with HIV/AIDS will be
employed (low quality evidence).
By affecting mainly young adults, AIDS reduces the taxable
population, in turn reducing the resources available for public expenditures such as education and
health services not related to AIDS resulting in increasing pressure for the
state's finances and slower growth of the economy. This causes a slower growth
of the tax base, an effect that is reinforced if there are growing expenditures
on treating the sick, training (to replace sick workers), sick pay and caring
for AIDS orphans. This is especially true if the sharp increase in adult
mortality shifts the responsibility and blame from the family to the government
in caring for these orphans.
At the household level, AIDS causes both loss of income and
increased spending on healthcare. A study in Côte d'Ivoire showed
that households having a person with HIV/AIDS spent twice as much on medical
expenses as other households. This additional expenditure also leaves less
income to spend on education and other personal or family investment.
Religion and AIDS
Main
article: Religion and HIV/AIDS
The topic of religion and AIDS has become highly controversial
in the past twenty years, primarily because some religious authorities have
publicly declared their opposition to the use of condoms. The religious
approach to prevent the spread of AIDS according to a report by American health
expert Matthew Hanley titled The Catholic Church and the Global AIDS
Crisis argues that cultural changes are needed including a re-emphasis
on fidelity within marriage and sexual abstinence outside of it.
Some religious organizations have claimed that prayer can cure
HIV/AIDS. In 2011, the BBC reported that some churches in London were claiming
that prayer would cure AIDS, and the Hackney-based Centre for the Study of
Sexual Health and HIV reported that several people stopped taking their
medication, sometimes on the direct advice of their pastor, leading to a number
of deaths. The Synagogue Church Of All Nations advertised
an "anointing water" to promote God's healing, although the group
denies advising people to stop taking medication.
Media portrayal
Main
article: Media portrayal of HIV/AIDS
One of the first high-profile cases of AIDS was the
American Rock Hudson, a gay actor who had been married and divorced
earlier in life, who died on October 2, 1985 having announced that he was
suffering from the virus on July 25 that year. He had been diagnosed during
1984. A notable British casualty of AIDS that year was Nicholas Eden, a gay politician and son of
the late prime minister Anthony Eden. On
November 24, 1991, the virus claimed the life of British rock star Freddie Mercury,
lead singer of the band Queen,
who died from an AIDS-related illness having only revealed the diagnosis on the
previous day. However, he had been diagnosed as HIV positive in 1987. One
of the first high-profile heterosexual cases of the virus was Arthur Ashe,
the American tennis player. He was diagnosed as HIV positive on August 31,
1988, having contracted the virus from blood transfusions during heart surgery
earlier in the 1980s. Further tests within 24 hours of the initial diagnosis
revealed that Ashe had AIDS, but he did not tell the public about his diagnosis
until April 1992. He died as a result on February 6, 1993 at age 49.
Therese Frare's photograph of gay activist David Kirby, as he lay dying from AIDS while
surrounded by family, was taken in April 1990. LIFE magazine said
the photo became the one image "most powerfully identified with the
HIV/AIDS epidemic." The photo was displayed in LIFE magazine,
was the winner of the World Press
Photo, and acquired worldwide notoriety after being used in a United Colors of Benetton advertising
campaign in 1992. In 1996, Johnson Aziga,
a Ugandan-born Canadian was diagnosed with HIV, but subsequently had
unprotected sex with 11 women without disclosing his diagnosis. By 2003 seven
had contracted HIV, and two died from complications related to AIDS. Aziga was
convicted of first-degree murder and was sentenced for
life.
Criminal transmission
Main
article: Criminal transmission of HIV
Criminal transmission of HIV is the intentional or reckless infection of a person with
the human immunodeficiency virus (HIV).
Some countries or jurisdictions, including some areas of the United States,
have laws that criminalize HIV transmission or exposure. Others may charge
the accused under laws enacted before the HIV pandemic.
Misconceptions
Main
articles: Misconceptions about HIV/AIDS and Discredited HIV/AIDS origins theories
There are many misconceptions about HIV and AIDS.
Three of the most common are that AIDS can spread through casual contact,
that sexual intercourse with a virgin will cure
AIDS, and that HIV can infect only gay men and drug users. In 2014, some
among the British public wrongly thought one could get HIV from kissing (16%),
sharing a glass (5%), spitting (16%), a public toilet seat (4%), and coughing
or sneezing (5%). Other misconceptions are that any act of anal
intercourse between two uninfected gay men can lead to HIV infection, and that
open discussion of HIV and homosexuality in schools will lead to increased
rates of AIDS.
A small group of individuals continue to dispute the connection
between HIV and AIDS, the existence of HIV itself, or the validity of HIV
testing and treatment methods. These claims, known as AIDS denialism,
have been examined and rejected by the scientific community. However, they
have had a significant political impact, particularly in South Africa, where the
government's official embrace of AIDS denialism (1999–2005) was responsible for
its ineffective response to that country's AIDS epidemic, and has been blamed
for hundreds of thousands of avoidable deaths and HIV infections.
Several discredited conspiracy theories have held that HIV was
created by scientists, either inadvertently or deliberately. Operation INFEKTION was a worldwide
Soviet active measures operation to spread the
claim that the United States had created HIV/AIDS. Surveys show that a
significant number of people believed – and continue to believe – in such
claims.
Research
Main
article: HIV/AIDS research
HIV/AIDS research includes all medical research which
attempts to prevent, treat, or cure HIV/AIDS along with fundamental research
about the nature of HIV as
an infectious agent and AIDS as the disease caused by HIV.
Many governments and research institutions participate in
HIV/AIDS research. This research includes behavioral health interventions such as sex education,
and drug development, such as research into microbicides for sexually transmitted
diseases, HIV vaccines, and antiretroviral drugs. Other medical research
areas include the topics of pre-exposure prophylaxis, post-exposure prophylaxis, and circumcision and HIV.
Source :
https://en.wikipedia.org/wiki/HIV/AIDS
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