27 November 2017 | Q&A

The human immunodeficiency virus (HIV) targets cells of the immune system, called CD4 cells, which help the body respond to infection. Within the CD4 cell the HIV replicates and in turn damages and destroys the cel.l Without effective treatment, using a combination of antiretroviral drugs, the immune system will become weakened to the point that it can no longer fight infection and disease.  

Acquired immunodeficiency syndrome (AIDS) is a term that applies to the most advanced stages of HIV infection. It is defined by the occurrence of any of the more than 20 life-threatening cancers or “opportunistic infections”, so named because they take advantage of a weakened immune system. AIDS was a defining feature of the earlier years of the HIV epidemic, before antiretroviral therapy (ART) became available. Now, as more and more people access ART, most people living with HIV do not progress to  AIDS. However, it is more likely to occur in people with HIV who have not been tested, in people who are diagnosed at a late stage of infection, and in people who are not taking ART.

For people living with HIV who are not diagnosed or taking ART, signs of HIV-related illness may develop within 5–10 years, although it can be sooner. The time between HIV transmission and an AIDS diagnosis is usually 10–15 years, but sometimes longer.


HIV is found in certain bodily fluids of people living with HIV, including blood, semen, vaginal fluids, rectal fluids and breastmilk. HIV can be transmitted by: 

  • unprotected vaginal or anal sex, and, in very rare cases, through oral sex with a person living with HIV;
  • blood transfusion of contaminated blood;
  • sharing of needles, syringes, other injecting equipment, surgical equipment or other sharp instruments; and
  • from a mother living with HIV to her infant during pregnancy, childbirth or breastfeeding. 
  • If a person living with HIV is on ART, which effectively suppresses HIV in the body, their chance of transmitting HIV to another person is greatly reduced. 

    While there is no cure for HIV infection, it can be treated using antiretroviral drugs, which work by stopping the replication of the virus. ART can reduce the level of virus to such low levels in the body that the immune system will function normally, and a person living with HIV can enjoy good health, provided they adhere to treatment and the treatment remains effective. People living with HIV are also much less likely to transmit the virus to others when treatment is working.


    Evidence from several studies show that people living with HIV who have an “undetectable” viral load cannot pass HIV on to others. A person is “undetectable” when ART has reduced the level of virus in their body to such low levels that it cannot be detected by normal viral load tests. Monitoring of viral load, and confirmation of an undetectable viral load, needs to be undertaken by a healthcare professional as part of the routine medical care for people with HIV. In many low- and middle-income countries, viral load tests are not consistently or routinely available, so many people do not benefit from the knowledge that they are undetectable. They can be assured, however, that the risk of transmitting HIV is greatly reduced when they adhere to treatment, and when treatment is started without delay. 

    ART allows people with HIV to live long and healthy lives by ensuring that their immune system remains healthy. In certain settings, however, many people living with HIV remain undiagnosed, not on treatment, or not taking consistent treatment, and, as a result their HIV disease progresses. 

    Tuberculosis (TB) is the number one cause of death among people living with HIV in Africa, and a leading cause of death among people living with HIV worldwide. Routine TB-symptom screening and early initiation of ART can greatly improve the health outcomes of people living with HIV. Other common HIV coinfections include hepatitis B and C in some populations. 

    HIV infection can result in a range of health problems. As people living with HIV age and live longer, non-AIDS defining illnesses are becoming more common. These include heart disease, cancer and diabetes. 

    Testing for HIV is the only way to know if a person has HIV or not. HIV can be diagnosed using rapid diagnostic tests that provide results within minutes. However, such results should only be considered as a full diagnosis following review and confirmation by a qualified health worker. 

    Knowledge of one’s HIV-positive status has two important benefits:

    • People who test positive can take steps to get treatment, care and support before symptoms appear, which can prolong life and prevent health complications for many years.
    • People who are aware of their status can take precautions to prevent the transmission of HIV to others. 

    WHO recommends that HIV tests be made available in all health facilities, in key community settings and at home via self-testing. 

    The main routes of HIV transmission include unsafe sex without condoms, receiving blood transfusions or other blood products contaminated with HIV, sharing of needles and syringes and other injecting equipment, being exposed to HIV through contaminated surgical and other skin piercing equipment and vertical transmission from mothers with HIV to their children. HIV is fully preventable; different interventions exist to stop transmission. 

    However, many people are not accessing necessary information and skills to prevent HIV. In some cases, major legal and social barriers prevent people from accessing effective prevention services and measures. Some populations are at higher risk of HIV infection, including men who have sex with men; people who inject drugs; people in prisons and other closed settings; sex workers and their clients; and transgender people. These populations are referred to as ‘key populations’, who are often marginalized in communities and experience major barriers in accessing HIV prevention and treatment and other health services. In some settings, other populations may be particularly vulnerable to HIV infection, such as adolescent girls in southern Africa.

    Globally, HIV is mainly transmitted through unprotected vaginal and anal sex. Several methods can be used to prevent this from happening. It is recommended that a combination of effective prevention interventions be used, including:

  • using male and/or female condoms consistently and correctly;
  • for HIV-negative people, taking pre-exposure prophylaxis of HIV (PrEP) to prevent HIV transmission;
  • for people living with HIV, taking ART to reduce viral load to undetectable levels, meaning they can’t transmit HIV to their sexual partners; and
  • being aware of one’s status to promote less risky sexual behaviours.
  • HIV can be transmitted from a mother to her child during pregnancy, labour, delivery or breastfeeding. But such vertical transmission can be prevented with effective interventions, including the use of ART by the mother and a short course of antiretroviral drugs for the baby. Other effective interventions include measures to prevent HIV acquisition in pregnant woman, prevent unintended pregnancies in women with HIV and appropriate breastfeeding practices. HIV testing services should be integrated into maternal and child health services, so that they women at risk can readily access testing. Pregnant women and mothers diagnosed with HIV should receive ART as soon as possible, so that their children are born free from HIV. 

    Pre-exposure prophylaxis, or PrEP, is a course of antiretroviral drugs that HIV-negative people can take to prevent HIV acquisition. When taken as recommended, it can practically eliminate the chance of acquiring HIV. PrEP is recommended for populations who are at higher risk of HIV. These groups may include men who have sex with men, sex workers, people who use drugs, and young women in southern Africa. 

    Male circumcision reduces the risk of sexual transmission from a woman to a man by around 60%. A one-time intervention, medical male circumcision provides life-long partial protection against HIV, as well as other sexually transmitted infections. It should always be considered as part of a comprehensive HIV prevention package, and should never replace other known methods of prevention, such as female and male condoms.


    When used correctly and consistently every time a person has sex, condoms are among the most effective means of preventing HIV infection in women and men. 

    No, there is currently no cure for HIV. But with good and continued adherence to ART, HIV infection can be contained and managed as a chronic health condition. In all parts of the world, people living with HIV are now surviving and thriving into old age. 


    While ART helps the immune system stay strong, people living with HIV can benefit from counselling and psychosocial support to ensure that they are truly “living well” with HIV. HIV is manageable, but it is a life-long chronic illness, and people may need support with their mental health and with lifestyle changes to support good health through life. Access to good nutrition, safe water and basic hygiene can also help people living with HIV to maintain a good quality of life. As with the general community, people living with HIV may experience a broad range of other health conditions that may need treatment and care. A people-centred approach to health care, particularly through primary health services, aims to deliver comprehensive health services to people living with HIV, in which all their health issues are addressed. 

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