About 571 000 people were newly-infected with HIV in 2005 in South Africa, a rate of about 1 500 new infections each day, the Human Sciences Research Council (HSRC) said on Wednesday.
HIV incidence in the population aged two years and older was 1.4 percent.
This emerged from research, led by the HSRC and published in the March issue of the South African Medical Journal, which assessed HIV incidence in South Africa. The incidence rate refers to the number of people infected with HIV over a single year, as opposed to the prevalence rate, which refers to the total number infected since the start of the epidemic.
An HIV incidence rate of 2.4 percent was found among people aged 15 to 49 years. About a third of all new HIV infections occurred in youth aged 15 to 24 years.
Women and girls hit hardest
The HSRC said the incidence rates among young women in the prime childbearing age were "especially alarming".
The incidence of HIV among women aged 20 to 29 was 5.6 percent - six times more than men of the same age. For youth aged 15 to 24, women and girls accounted for 90 percent of all recent infections.
"These findings suggest that the current prevention campaigns do not have the desired impact, particularly among young women," concluded Professor Thomas Rehle, director in the social aspects of HIV/Aids and health research programme at the HSRC.
Rehle wrote the article, together with HSRC president Dr Olive Shisana, Dr Victoria Pillay, Khangelani Zuma, Adrian Puren and Warren Parker.
The incidence analysis also showed that a substantial number of new non-vertical infections - those not transferred from mother to child - had occurred among children in South Africa.
"The causes of these non-vertical transmissions still need further investigation... (to) understand cause and effect," said Shisana.
Researchers found that people living in urban informal settlements had "by far the highest incidence rates" at 5.1 percent, followed by those in rural informal areas (1.6 percent) and urban formal areas (0.8 percent).
Poverty plays significant role
"These results suggest that poverty plays a significant role in increasing vulnerability to HIV," said Shisana.
"An encouraging finding of the study was that reported condom use in the younger age group is associated with substantially lower HIV incidence, particularly among young males," said Pillay, a research specialist at the HSRC.
A surprising finding was the high HIV incidence among widowed individuals of 5.8 percent, especially among women.
Pregnancy was identified as a significant risk factor for HIV.
Among women and girls between 15 and 49 years, 5.2 percent of the pregnant women were newly infected compared to 3.7 percent of the non-pregnant women.
Provides critical new insights
"Incidence data provide critical new insights into the dynamics of the HIV epidemic and are a more appropriate measure to correlate biological data with recent behaviours or recent behavioural changes," said Rehle.
"The 2005 national HIV incidence estimates presented in this study will serve as benchmark figures for future assessments of the dynamics and trends of the South African HIV epidemic."
The analysis was based on data from the "South African national HIV prevalence, HIV incidence, behaviour and communication survey, 2005", commissioned by the Nelson Mandela Foundation with support from the US Centres for Disease Control and Prevention.
It looked at "an unparalleled large sample of 15 851 blood specimens" which were analysed to estimate HIV incidence nationally. – (Sapa)