A Kenyan scientist has praised a method that offers partial protection against HIV in women.
According to two studies, the vaginal silicone ring prevented HIV by between 27 and 31 per cent through releasing an antiviral drug -- dapivirine -- gradually over a month.
But the protection was not as high as expected by the researchers conducting the study in more than 4,500 women in Uganda, Malawi, South Africa and Zimbabwe.
Kenya Medical Research Institute senior scientist Nelly Mugo said she was excited about the results, saying they were a major advance in the search for HIV prevention.
"This will be great for discordant couples, where one is HIV positive and the other isn't. It will be a good prevention method for adolescent girls and young women, as one in four new HIV infections in sub-Saharan Africa occurs in this group," she said.
Kenya has the world's fourth largest HIV numbers with an estimated 1.63 million people, and nearly 100,000 new infections every year.
The ring, which is 2.5 inches in diameter and costs about Sh500, is left in the vagina for 28 days and is then replaced.
Future versions of the ring, according to Ms Kay Marshall from AVAC, an HIV prevention advocacy group, will last three months, and some will combine antiviral medication with family planning.
If introduced in Kenya, the ring would complement another method for prevention called Truvada.
It was approved by the Kenya Pharmacy and Poisons Board in December last year.
Unlike the rings, the daily oral pills are used by uninfected men and women for prevention of HIV.
All study participants either had multiple sex partners or were at risk of HIV infection and as such, received free condoms, packages of HIV prevention services at every study visit, counselling, partner testing and treatment of sexually transmitted infections of them and their partners.
The first study by Microbicide Trials Network enrolled 2,629 women aged 18 to 45 in Malawi, South Africa, Uganda and Zimbabwe.
The second project -- the Ring Study -- led by International Partnership for Microbicide, enlisted 1,959 women in South Africa and Uganda.