HIV/AIDS
Key facts
- HIV continues to be a major global public health issue, having claimed more than 34 million lives so far. In 2014, 1.2 [980 000–1.6 million] million people died from HIV-related causes globally.
- There were approximately 36.9 [34.3–41.4] million people living with HIV at the end of 2014 with 2.0 [1.9–2.2] million people becoming newly infected with HIV in 2014 globally.
- Sub-Saharan Africa is the most affected region, with 25.8 [24.0–28.7] million people living with HIV in 2014. Also sub-Saharan Africa accounts for almost 70% of the global total of new HIV infections.
- HIV infection is often diagnosed through rapid diagnostic tests (RDTs), which detect the presence or absence of HIV antibodies. Most often these tests provide same day test results; essential for same day diagnosis and early treatment and care.
- There is no cure for HIV infection. However, effective antiretroviral (ARV) drugs can control the virus and help prevent transmission so that people with HIV, and those at substantial risk, can enjoy healthy and productive lives.
- It is estimated that currently only 54% of people with HIV know their status. In 2014, approximately 150 million children and adults in 129 low- and middle-income countries received HIV testing services.
- By mid-2015, 15.8 million people living with HIV were receiving antiretroviral therapy (ART) globally.
- Between 2000 and 2015, new HIV infections have fallen by 35%, AIDS-related deaths have fallen by 24% with some 7.8 million lives saved as a result of international efforts that led the global achievement of the HIV targets of the Millennium Development Goals.
- Expanding ART to all people living with HIV and expanding prevention choices can help avert 21 million AIDS-related deaths and 28 million new infections by 2030.
The Human Immunodeficiency Virus (HIV) targets the immune system and weakens people's defence systems against infections and some types of cancer. As the virus destroys and impairs the function of immune cells, infected individuals gradually become immunodeficient. Immune function is typically measured by CD4 cell count. Immunodeficiency results in increased susceptibility to a wide range of infections and diseases that people with healthy immune systems can fight off.
The most advanced stage of HIV infection is Acquired Immunodeficiency Syndrome (AIDS), which can take from 2 to 15 years to develop depending on the individual. AIDS is defined by the development of certain cancers, infections, or other severe clinical manifestations.
Signs and symptoms
The symptoms of HIV vary depending on the stage of infection. Though people living with HIV tend to be most infectious in the first few months, many are unaware of their status until later stages. The first few weeks after initial infection, individuals may experience no symptoms or an influenza-like illness including fever, headache, rash or sore throat.
As the infection progressively weakens the immune system, an individual can develop other signs and symptoms, such as swollen lymph nodes, weight loss, fever, diarrhoea and cough. Without treatment, they could also develop severe illnesses such as tuberculosis, cryptococcal meningitis, and cancers such as lymphomas and Kaposi's sarcoma, among others.
Transmission
HIV can be transmitted via the exchange of a variety of body fluids from infected individuals, such as blood, breast milk, semen and vaginal secretions. Individuals cannot become infected through ordinary day-to-day contact such as kissing, hugging, shaking hands, or sharing personal objects, food or water.
Risk factors
Behaviours and conditions that put individuals at greater risk of contracting HIV include:
- having unprotected anal or vaginal sex;
- having another sexually transmitted infection such as syphilis, herpes, chlamydia, gonorrhoea, and bacterial vaginosis;
- sharing contaminated needles, syringes and other injecting equipment and drug solutions when injecting drugs;
- receiving unsafe injections, blood transfusions, medical procedures that involve unsterile cutting or piercing; and
- experiencing accidental needle stick injuries, including among health workers.
Diagnosis
Serological tests, such as RDTs or enzyme immunoassays (EIAs), detect the presence or absence of antibodies to HIV-1/2 and/or HIV p24 antigen. When such tests are used within a testing strategy according to a validated testing algorithm, HIV infection can be detected with great accuracy. It is important to note that serological tests detect antibodies produced by an individual as part of their immune system to fight off foreign pathogens, rather than direct detection of HIV itself.
Most individuals develop antibodies to HIV-1/2 within 28 days and therefore antibodies may not be detectable early after infection, the so-called window period. This early period of infection represents the time of greatest infectivity; however HIV transmission can occur during all stages of the infection.
It is best practice to also retest all people initially diagnosed as HIV-positive before they enrol in care and/or treatment to rule out any potential testing or reporting error.
HIV testing services
HIV testing should be voluntary and the right to decline testing should be recognized. Mandatory or coerced testing by a health-care provider, authority or by a partner or family member is not acceptable as it undermines good public health practice and infringes on human rights.
Some countries have introduced, or are considering, self-testing as an additional option. HIV self-testing is a process whereby a person who wants to know his or her HIV status collects a specimen, performs a test and interprets the test results in private. HIV self-testing does not provide a definitive diagnosis; instead, it is an initial test which requires further testing by a health worker using a national validated testing algorithm.
All HIV testing services must include the 5 C’s recommended by WHO: informed Consent, Confidentiality, Counselling, Correct test results and Connection (linkage to care, treatment and other services).
Prevention
Individuals can reduce the risk of HIV infection by limiting exposure to risk factors. Key approaches for HIV prevention, which are often used in combination, include:
1. Male and female condom use
Correct and consistent use of male and female condoms during vaginal or anal penetration can protect against the spread of sexually transmitted infections, including HIV. Evidence shows that male latex condoms have an 85% or greater protective effect against HIV and other sexually transmitted infections (STIs).
2. Testing and counselling for HIV and STIs
Testing for HIV and other STIs is strongly advised for all people exposed to any of the risk factors. This way people learn of their own infection status and access necessary prevention and treatment services without delay. WHO also recommends offering testing for partners or couples.
Tuberculosis (TB) is the most common presenting illness among people with HIV. It is fatal if undetected or untreated and is the leading cause of death among people with HIV- responsible for 1 of every 3 HIV-associated deaths. Early detection of TB and prompt linkage to TB treatment and ART can prevent these deaths. It is strongly advised that HIV testing services integrate screening for TB and that all individuals diagnosed with HIV and active TB urgently use ART.
3. Voluntary medical male circumcision
Medical male circumcision, when safely provided by well-trained health professionals, reduces the risk of heterosexually acquired HIV infection in men by approximately 60%. This is a key intervention in generalized epidemic settings with high HIV prevalence and low male circumcision rates.
4. Antiretroviral (ART) use for prevention
4.1 ART as prevention
A 2011 trial has confirmed if an HIV-positive person adheres to an effective ART regimen, the risk of transmitting the virus to their uninfected sexual partner can be reduced by 96%. The WHO recommendation to initiate ART in all people living with HIV will contribute significantly to reducing HIV transmission.
4.2 Pre-exposure prophylaxis (PrEP) for HIV-negative partner
Oral PrEP of HIV is the daily use of ARV drugs by HIV-uninfected people to block the acquisition of HIV. More than 10 randomized controlled studies have demonstrated the effectiveness of PrEP in reducing HIV transmission among a range of populations including serodiscordant heterosexual couples (where one partner is infected and the other is not), men who have sex with men, transgender women, high-risk heterosexual couples, and people who inject drugs.
In September 2015, WHO published the “Guideline on when to start antiretroviral therapy and on pre-exposure prophylaxis for HIV”, that recommends PrEP as a prevention choice for people at substantial risk of HIV infection as part of combination prevention approaches.
4.3 Post-exposure prophylaxis for HIV (PEP)
Post-exposure prophylaxis (PEP) is the use of ARV drugs within 72 hours of exposure to HIV in order to prevent infection. PEP includes counselling, first aid care, HIV testing, and administering of a 28-day course of ARV drugs with follow-up care.
Updated WHO guidelines issued in December 2014 recommend PEP use for both occupational and non-occupational exposures and for adults and children. The new recommendations provide simpler regimens using ARVs already being used in treatment. The implementation of the new guidelines will enable easier prescribing, better adherence and increased completion rates of PEP to prevent HIV in people who have been accidentally exposed to HIV such as health workers or through unprotected sexual exposures or sexual assault.
5. Harm reduction for injecting drug users
People who inject drugs can take precautions against becoming infected with HIV by using sterile injecting equipment, including needles and syringes, for each injection. A comprehensive package of interventions for HIV prevention and treatment includes:
- needle and syringe programmes;
- opioid substitution therapy for people dependent on opioids and other evidence based drug dependence treatment;
- HIV testing and counselling;
- HIV treatment and care;
- access to condoms; and
- management of STIs, tuberculosis and viral hepatitis.
6. Elimination of mother-to-child transmission of HIV (EMTCT)
The transmission of HIV from an HIV-positive mother to her child during pregnancy, labour, delivery or breastfeeding is called vertical or mother-to-child transmission (MTCT). In the absence of any interventions during these stages, rates of HIV transmission from mother-to-child can be between 15-45%. MTCT can be nearly fully prevented if both the mother and the child are provided with ARV drugs throughout the stages when infection could occur.
WHO recommends options for prevention of MTCT (PMTCT), which includes providing ARVs to mothers and infants during pregnancy, labour and the post-natal period, and offering life-long treatment to HIV-positive pregnant women regardless of their CD4 count.
In 2014, 73% [68–79%] of the estimated 1.5 [1.3-1.6] million pregnant women living with HIV globally received effective antiretroviral drugs to avoid transmission to their children.
Treatment
HIV can be suppressed by combination ART consisting of 3 or more ARV drugs. ART does not cure HIV infection but controls viral replication within a person's body and allows an individual's immune system to strengthen and regain the capacity to fight off infections.
In 2015, WHO released a new "Guideline on when to start antiretroviral therapy and on pre-exposure prophylaxis for HIV.” The guidelines recommend that anyone infected with HIV should begin antiretroviral treatment as soon after diagnosis as possible.
By mid-2015, 15.8 million people living with HIV were receiving ART globally. By end of 2014, 40% [37–45%] of all people living with HIV were on ART.
Based on WHO’s new recommendations, to treat all people living with HIV and offer antiretrovirals as an additional prevention choice for people at "substantial" risk, the number of people eligible for antiretroviral treatment increases from 28 million to all 37 million people. Expanding access to treatment is at the heart of a new set of targets for 2020 which aim to end the AIDS epidemic by 2030.
WHO response
WHO is working with countries to implement the Global Health Sector Strategy on HIV/AIDS for 2011-2015. WHO has identified 6 operational objectives for 2014–2015 to support countries most efficiently in moving towards the global HIV targets. These are to support:
- strategic use of ARVs for HIV treatment and prevention;
- the elimination HIV in children and expanding access to paediatric treatment;
- an improved health sector response to HIV among key populations;
- further innovation in HIV prevention, diagnosis, treatment and care;
- strategic information for effective scale up;
- stronger links between HIV and related health outcomes.
Currently, WHO is working on a new strategy for the global health sector response to HIV for 2016-2021. WHO is a cosponsor of the Joint United Nations Programme on AIDS (UNAIDS). Within UNAIDS, WHO leads activities on HIV treatment and care, HIV and tuberculosis co-infection, and jointly coordinates with UNICEF the work on the elimination of mother-to-child transmission of HIV.