Infection with the human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS), which affects the cells of the immune system, and destroys or impairs their function. The virus is transmitted through direct contact with an infected mucosal membrane or bodily fluids such as blood, semen, and breast milk.  After an initial frequently asymptomatic phase, skin problems and upper respiratory tract infections develop, and patients begin to lose weight.  Chronic diarrhoea, persistent fever, fungal or bacterial infections, and tuberculosis may follow.  As the disease progresses, the immune system deteriorates, slowly losing its ability to fight other infections and diseases, and ultimately leading to “immune deficiency”.

Immunodeficient people are prone to opportunistic infections and cancers. There is no cure or vaccine currently available, but the availability of effective antiretroviral therapy has significantly decreased mortality and increased survival times of HIV-infected people in high-income countries. However, antiretroviral drugs are generally expensive, and access to diagnostic tests and treatments in low- to middle-income countries has been insufficient. Over the past decade, competition from generic pharmaceutical companies has dramatically decreased the price of antiretrovirals, although newer generation drugs remain prohibitively expensive.

Most children acquire HIV through perinatal transmission during pregnancy, childbirth, or whilst breast-feeding. Prevention programmes can reduce the risk of transmission from 30-40% down to less than 5%. Increased access to these programmes will lead to better health of HIV-positive pregnant women and to lower numbers of infants infected. Infants who acquire HIV around delivery develop the disease rapidly during the first few months and die, often before they are even diagnosed with the virus.

Wold Map showing the number of children (<15 years) living with HIV in 2016
The global number of children (<15 years) living with HIV in 2016. Source: UNAIDS, http://aidsinfo.unaids.org/
Whereas in high-income countries most HIV-positive pregnant women have access to good quality antenatal care and receive antiretroviral therapy, women in resource-limited settings have little access to these services. Moreover, pregnant women with HIV in high-income countries are advised to use reconstituted formula milk, whereas in developing countries safe drinking water is often not readily available and the risk of acquiring infections from bottle-feeding can be high. HIV progression is more rapid in children than in adults, and the disease has a more devastating effect on an infant’s body.  Children fail to grow and gain weight at the normal rate, and may experience feeding difficulties due to oral thrush, mouth sores or loss of appetite, or malabsorption due to persistent diarrhoea. Severe wasting is common, and can be exacerbated by malnutrition, leading to life-threatening problems. Sub-Saharan Africa accounts for 88% of children living with HIV, and 86% of new infections in children. Tuberculosis (TB) is currently the leading cause of death of people living with HIV in Africa and HIV-positive children are more susceptible to TB infection.

 
Increased financial resources and political commitments over the last decade have led to great progress in diagnosing and treating people with HIV/AIDS in resource-limited settings, with an estimated 20.9 million people with HIV/AIDS now receiving antiretroviral therapy. Death rates have begun to decline where access to treatments is high, and new HIV infections are beginning to stabilize in epidemic areas. However, there are still millions of people in need of treatment today who are going without, and an even more pronounced “treatment gap” for children – only 43% of children who need ART are currently receiving it, whereas about 54% of adults living with HIV have access to treatment.