Johannesburg - Within a few years, women might be able to insert a vaginal ring to protect them from HIV infection and pregnancy.

Rings that slowly release antiretroviral (ARV) medicine into a woman’s vagina are in advanced clinical testing, with trial results expected next year. Researchers believe it will be easy to insert a contraceptive into the ring as well.

“About 92 percent of couples globally don’t use condoms, so it is important to develop other options,” said Sharon Hillier from the University of Pittsburgh Medical School in the US.

The ring will offer women a discreet way of preventing HIV, undetected by their partners.

Some of the world’s top HIV researchers are in Cape Town this week at the first global HIV Research for Prevention (HIVR4P) conference.

Using antiretroviral medication to prevent – not just treat – HIV is emerging as one of the most powerful weapons to contain the epidemic in the absence of a vaccine.

ARVs taken immediately after HIV exposure – in rape cases or when health workers are injured by needles while treating HIV-positive patients – have been known to prevent HIV.

More recently, the results were released of Dr Myron Cohen’s 10-year study of couples where one person was HIV-positive and the other negative.

It found that if the HIV-positive partner was on ARVs and their viral load was undetectable, their negative partner was 96 percent protected from HIV infection.

A number of “treatment as prevention” studies have also shown that ARVs taken shortly before sex by people at high risk of HIV offer protection against HIV.

Truvada, a pill that combines the ARVs tenofovir and emtricitabine, reduced HIV transmission in gay men by 42 percent.

Long-acting injections containing ARVs that would have to be given only every two to three months are also in the pipeline, researchers said on Wednesday.

These would make it much easier for people to adhere to treatment and are also being tested to see whether they can protect HIV-negative people from the virus.

Wits University’s Professor Helen Rees, who is a conference co-chair, said it was more realistic to control rather than eradicate the epidemic at this stage.

Dr Anthony Fauci, head of the US National Institute of Allergy and Infectious Diseases, told the 1 300 delegates that comprehensive HIV prevention rested on the “synergy between vaccine and non-vaccine research”.

Researchers envisage that people can be offered a “smorgasbord” of prevention methods – including condoms, ARVS and the possibility of a partially effective vaccine.

Since 2009, when a vaccine trial in Thailand showed “modest” protection for around 30 percent of people after two years, researchers have been unravelling exactly how it worked.

One of the key focus areas is how some of the Thai trialists were able to develop antibodies to partially protect themselves from HIV, and the quest for “broadly neutralising antibodies” is a cornerstone of vaccine research.

The Thai vaccine has been tested on South Africans in the past two years, and they showed the same antibody response.

Within 18 months, South Africa could host a massive trial of a modified and improved version of the Thai vaccine involving 7 000 people and costing R1 billion, according to Medical Research Council president Dr Glenda Gray. – Health-e News Service