Durban - The prevalence of HIV in South Africa is highest in KwaZulu-Natal.

This was among the findings of a major national HIV study, the results of which were released by the Human Sciences Research Council (HSRC) on Tuesday.

The study – titled the South African National HIV Prevalence, Incidence and Behaviour Survey – involved interviews with nearly 40 000 people across the country in 2012. Similar studies were carried out in 2002, 2005 and 2008.

KwaZulu-Natal, where almost 28 percent of people are HIV-positive, remains the province with the highest HIV prevalence, while the Western Cape has the lowest prevalence at nearly 8 percent.

Other provinces with a prevalence above 20 percent include Mpumalanga, Free State, and North West.

The study also found that South Africa has the largest antiretroviral treatment (ART) programme in the world – but with 400 000 new infections in 2012, it also ranks first in HIV incidence.

The study found about 6.4 million people living with HIV/Aids in South Africa in 2012, and that more than two million of them were on ART.

More people with HIV were living longer because of the government’s “hugely expanded” treatment programme, the study found.

However, there was a decline in condom use, an increase in multiple sexual partnerships, while some of the risky sexual behaviours partly accounted for “so many” new infections.

The HIV incidence rate among females in the 15-24 category was found to be four times higher than for their male counterparts (2.5 percent vs 0.6 percent), while black African women aged 20-34 had the highest incidence of HIV among the analysed population groups.

Another concern was that the majority of the survey respondents (76.5 percent) aged 15 years and older believed they were at low risk of acquiring an infection.

“Unfortunately, one in 10 who believed (this) … was already infected, but didn’t know it,” the study reported.

And the overall knowledge about how HIV is transmitted and prevented also declined, from 30.3 percent in 2008 when the previous survey was carried out to 26.8 percent in 2012.

Professor Olive Shasana, the chief executive of the HSRC, said these disproportionately high levels among females, as well as the the high HIV prevalence in unmarried cohabiting people (3.08 percent), called for a strategy that addressed the underlying socio-cultural norms in the affected communities.

Another principal investigator, Professor Lieckness Simbayi, executive director of the HIV/Aids, Sexually Transmitted Infections and TB programme at the HSRC, said South Africans should not be complacent about prevention.

People needed to continue to engage in safer sex practices to prevent new infections.

The study also noted a slight decline of HIV prevalence in the 15-24 age group, from 8.7 percent in 2008 to 7.3 percent in 2012.

As a result of the successful prevention of mother-to-child transmission programme, HIV infection levels had further decreased among infants 12 months and younger, from 2.0 percent in 2008 to 1.3 percent in 2012.

Attitudes towards people living with HIV had also “improved considerably”, partly as a result of the wider availability of ART, and because many people had been tested and knew their HIV status.