South Africa is currently the country with the largest number of people living with HIV in the world. Many children are HIV positive or have become ill and died due to AIDS. The majority of children are infected before and during the birth process and some later through breastfeeding. Children may also become infected through sexual intercourse, including sexual abuse.
It is important to have an estimate of the number of children in the country infected with HIV to plan for health services to meet their needs adequately. In addition, knowing the prevalence from year to year also helps to monitor the epidemic and gives an indication of the effectiveness of prevention measures such as the prevention of mother-to-child transmission (PMTCT) programme.
In a 2008 national household survey conducted by the Human Sciences Research Council, the prevalence of HIV measured in children aged 2 – 14 was 2.5% (95% CI:1.9 – 3.5%). This was slightly lower than the proportion who tested positive in a similar survey in 2005 (3.3%, 95% CI: 2.3 – 4.8%), though not significantly so. An earlier survey, conducted in 2002, suggested that the HIV prevalence in the 2 – 14 age group was 5.6%, but this is likely to be an over-estimate, because this survey used a testing algorithm with relatively low specificity (a single saliva test with no confirmatory testing of positive specimens).
The HSRC survey reports provincial prevalence of HIV in children 2 – 14 years old. However the related 95% confidence intervals are extremely wide, and thus little can be inferred from the data. In both the 2005 and 2008 surveys, the Western Cape is identified as the province with the lowest HIV prevalence in children.
Although the ASSA2003 AIDS and Demographic model has been widely used in the past for the purpose of estimating HIV prevalence in children, recent evidence suggests that this model may be understating the HIV prevalence in children. This is partly because the model does not take into account vertical transmission from mothers who become infected in late pregnancy or while breastfeeding. It is also partly because the model assumptions about the expansion of the prevention of mother-to-child transmission (PMTCT) programme are too optimistic. It is also possible that the model may be over-estimating the mortality rate in HIV-infected children. The paediatric HIV assumptions in the ASSA2003 model are currently under review and are likely to change in the next version of the model that is released.