Swaziland's first case of HIV was diagnosed in 1986. According to the 2010 UNAIDS Report on the Global AIDS Epidemic, Swaziland has the highest HIV prevalence in the world at 25.9 per cent for the population aged 15–49. According to the 2007 Demographic and Health Survey, HIV prevalence among 15–49 year olds is higher among females than males at 31 per cent and 20 per cent, respectively. Females have higher prevalence within younger age groups until the ages 30–34, while males have higher prevalence thereafter. Females peak earlier; the most affected age group is 25–29 years for females and 35–39 years for males.
HIV prevalence among pregnant women aged 15–49 seeking antenatal care in government health facilities is higher than the national average. HIV prevalence in pregnant women has increased dramatically from 3.9 percent in 1992 to a peak of 42.6 percent in 2004. The current prevalence rate is 41.1 percent. Antenatal care data reveals that HIV prevalence among younger age groups has declined, whereas that of older women has increased as the epidemic has matured. HIV prevalence within the age group 15–19 was 32.5 per cent in 2002 and is now 26.3 per cent, while that of women aged 30–34 years was 29.6 per cent in 2002 and has almost doubled to 53.8 per cent by 2008.
The percentage of people aged 15–49 who know their status has improved from 16 per cent in 2007 to 40 per cent, comprising of 47 per cent women and 31 per cent men. Those who have ever been married or are currently married are more likely to be tested than their unmarried counterparts.
There were about 182,800 adults and 14,300 children living with HIV in Swaziland at the end of 2011. From those, 58 per cent were female. There is an estimated average of more than 11,000 new infections every year, the majority of which occur through heterosexual sex and among those aged 25 and older.
According to the 2010 Multiple Indicator Cluster Survey, 45 per cent of all children under 18 are classified as either orphaned or vulnerable. Only 22 per cent of children under the age of 18 live in a household with both biological parents and 33 per cent live with neither biological parent. The impact of HIV is manifested through an increase in the mortality rate and subsequent decline in life expectancy, from 60 years in the 1990s to an estimated 42 and 43 years for men and women, respectively in 2007. With the successful antiretroviral treatment programme, life expectancy is expected to increase to 46 years in 2015.
According to Ministry of Health programme data, there were 72,402 people living with HIV (65,835 adults and 6,567 children) who were receiving antiretroviral treatment (ART) at the end of 2011. This corresponds to 80 per cent coverage of all those in need. Additionally, through a successful prevention of mother-to-child transmission (PMTCT) programme, over 90 per cent HIV-positive pregnant women receive antiretroviral prophylaxis to prevent vertical transmission. This is attributed to a high antenatal care attendance and HIV testing during antenatal care visits, which are 97 per cent and 87 per cent, respectively. Similarly, only two per cent of children aged 6–8 weeks born to HIV-positive mothers contract HIV, demonstrating that Swaziland is well on course to eliminating mother-to-child transmission.