New data from Swaziland, a tiny country in southern Africa, provide some of the most convincing evidence yet that aggressively ramping up treatment for HIV/AIDS work on a population level to cut the rate of new infections. The kingdom has had one of the worst HIV/AIDS epidemics in the world, but since 2011, its massive scale-up of testing and treatment has slashed the rate of new infections by 44%.
Several studies have firmly established that when antiretroviral drugs (ARVs) are taken consistently they drive the level of HIV in the blood down below the level of detection on standard tests. In response, the risk of an infected person transmitting the virus plummets. This led to the concept of so-called treatment as prevention, and mathematical models suggest that if 73% of a population suppresses their virus, new infection rates will nose-dive and epidemics can sputter out. But many questions remain about this theory, especially after a report last year showed that Botswana had come close to hitting this target without seeing much impact on its rate of new infections.
New data presented here at the International AIDS Society’s (IAS’s) international conference show Swaziland, a landlocked country of 1.45 million people that’s bordered by South Africa and Mozambique, has made “remarkable progress,” said Velephi Okello from the country’s Ministry of Health in Mbabane.
As Okello explained, a survey in 2011 showed that 32% of the Swazi population between the ages of 18 and 49 was living with HIV—the highest prevalence of any country in the world. At the time, only 72,402 of those people were receiving ARV treatment. Only 34.8% of the infected population had suppressed the virus. The rate of new infection, or incidence, was 2.5% per year.