After a steep increase in the 1990s, and several years of plateauing, South Africa's HIV prevalence may finally have entered a phase of decline.
The first evidence of this downward trend comes from the government's 2006 National HIV and Syphilis Survey, which tested more than 33,000 pregnant women at antenatal clinics in all nine of the country's provinces.
Twice the size of the previous such survey, the study showed a small overall decline in prevalence from 30.2% in 2005 to 29.1% in 2006, and larger declines in the under 24 age group. Most encouragingly, according to the department of health, HIV prevalence among women under 20 fell from 16.1% in 2004 to 13.7% in 2006.
Using the survey results to project the country's total HIV burden, the department of health now estimates that 5.41 million South Africans are living with the virus, slightly lower than the previous estimate of 5.54 million.
South Africa's Minister of Health, Manto Tshabalala-Msimang, highlighted some of the survey results in a June speech to parliament, but the full survey was released on Thursday.
Introducing the report at a press conference in Johannesburg, Tshabalala-Msimang described the new figures, as "a good indicator of the impact of the country's prevention programmes".
Dr Lindiwe Makubalo of the ministry of health, who led the research, noted that the decline in prevalence in younger age groups was the best indication available that HIV incidence (the number of new infections) was slowing and that the decline in HIV prevalence had not been caused by high death rates resulting from AIDS.
"I think it's something we must celebrate as South Africans, and say, 'thank you', to the youth of this country, because we think they are beginning to take prevention messages seriously," Tshabalala-Msimang told journalists.
To comments from her audience that the continued rise in mortality rates among prime-aged adults and an estimated 500,000 new HIV infections a year were hardly cause for celebration, Tshabalala-Msimang responded that it was important to "send out positive messages; messages of hope and encouragement - I think that motivates people to do more."
The report also showed that syphilis infections, an important indicator of risky sexual behaviour and a contributing factor to the acquisition of HIV, have been falling steadily over the last ten years from 11.2% in 1997 to 1.8% in 2006. Tshabalala-Msimang attributed the decline to "a number of intervention activities and, in particular, good quality STI (sexually transmitted infections) management and treatment."
But the survey's results were not all encouraging: among pregnant women over the age of 30, HIV prevalence increased from 34.4% in 2004 to 37% in 2006 in the 30 to 34 age group, and from 24.5% to 29.3% in the 35 to 39 age group.
Makubalo explained that some of the rise in prevalence could be attributed to young women with HIV living into their thirties. However, it could also indicate that older women were more likely to be in long-term relationships and, possibly, less able to avoid unprotected sex.
Unlike previous antenatal surveys, which only presented results by province, the 2006 survey showed some surprisingly large disparities in HIV prevalence between districts. In Northern Cape Province, for example, the western district of Namakwa showed a prevalence of 5.3% while the Frances Baard District in the east, had an infection rate of 22.7%.