Paris - Swaziland, which bears the world's heaviest HIV burden, has halved the rate of new infections in five years by boosting access to virus-suppressing drugs, researchers said Monday.The country where about one in three adults are infected with the AIDS-causing virus, has vastly expanded public programmes to test people for HIV infection and put them on life-saving anti-retroviral treatment (ART)."Since 2011, national HIV incidence in Swaziland dropped by almost half," a research team led by Velephi Okello of the Swazi health ministry said in a written presentation to an HIV science conference in Paris.Incidence is the word used by epidemiologists for the rate of new infections in a population."Sustaining these achievements will be paramount to Swaziland's success in curbing its severe HIV epidemic," said the researchers.In 2011, 31% of adults (aged 18-49) out of a total country population of just over 1.2 million, were infected with HIV, according to government data.Improved HIV treatment This made Swaziland the country with the highest national rate of new infections, said the authors of the new study, as well as the highest proportion of people living with HIV.The latest data, based on blood tests from about 11 000 people aged 15 and over, showed that 27% were HIV-positive in 2016.This translated to an infection rate of 1.39% among 18- to 49-year-olds, down from 2.58% in 2011 - a 46% reduction."Incidence was higher among women than in men," said the report to the International Aids Society conference. The decline was also steeper for men at 52% than for women at 40%.The survey showed that 73% of people on ART had achieved suppression of the virus, compared to 35% in 2011.ART not only stops HIV from replicating and attacking a patient's immune system, but also curbs its spread to sexual partners.The gains were the fruit of a much improved HIV treatment programme, said the researchers.The number of HIV tests conducted in Swaziland more than doubled from 176 000 in 2011 to 367 000 in 2016, and the share of infected people on ART rose from 37% to 74%.