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CAPE TOWN – Vaginal rings filled with antiretrovirals (ARVs), ARV injections and partially effective vaccines are some of the HIV prevention weapons under development.
Nonthando Kewana will soon know if her monthly trips to the Emavundleni Research Centre in Crossroads have made history.
For almost two years, 25-year-old Kewana has been paying monthly visits to the centre to get a vaginal ring that slowly releases an antiretroviral into her body.
She is part of the final phase of a big clinical trial, and researchers expect to know by mid-2015 whether the ring can protect women from HIV.
“I was scared when I saw the ring, and I thought it might go all around my body but I don’t even feel it,” Kewana said this week, as she waited for her monthly appointment. “My partner also can’t feel it.”
The ring is a white, silicone hoop about the size of the circle made when a woman’s thumb and forefinger join up.
Over 3000 women around the continent are involved in the ASPIRE trial, which is testing whether the ARV called Dapivirine can protect women from HIV through the simple ring that stays in place for a month.
“I decided to come here to see if I can protect myself from HIV, because I am so scared of it,” said Kewana, who witnessed her older sister die of AIDS.
Emavundleni is part of the Desmond Tutu HIV Foundation headed by world-renowned HIV expert Professor Linda-Gail Bekker.
“This area encapsulates the worst of Cape Town’s HIV epidemic, with about 28 to 30 percent of pregnant women testing HIV positive,” said Bekker this week. “HIV is particularly high in the very informal parts, where people are newly urbanized and don’t have ready access to healthcare. That is why this research has to happen here.”
The centre was set up 10 years ago in a shipping container and has since grown into a two-storey building. Researchers have worked very hard to win the trust of community members and encourage them to take part in a number of HIV trials. Currently, over 500 people from Crossroads and Nyanga are involved in various HIV and TB prevention trials.
New HIV prevention trials to take science out of lab and into communities
This week, the globe’s leading brains researching biomedical ways of preventing HIV met in Cape Town for the inaugural HIV Research for Prevention conference.
“We have six and a half million people living with HIV in South Africa, and treating them with ARVs for the rest of their lives is an enormous public health undertaking,” said Bekker. “There is an urgency to turn off the taps [of infection] and come up with new prevention methods.”
Using ARV 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 healthworkers are injured by needles while treating HIV positive patients – have been known to prevent HIV.
Three years ago, the results of Dr Myron Cohen’s 10-year study of couples where one person was HIV positive and the other negative, were released. The study 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. For example, 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 only have to be given every two to three months are also in the pipeline, and one of these will be tested at Emavundleni from February.
These injections 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 was a conference co-chair, said it was more realistic to control rather than eradicate the HIV epidemic at this stage.
However, the long-term aim is still a vaccine to prevent HIV, and there are some exciting developments.
Six years ago, the world heard the results of the only vaccine that showed any protective effects, protecting around one-third of Thai people in a huge trial.
For the past two years, the same Thai vaccine has been tested on 100 South Africans – and despite being much fatter than their Thai counterparts, their immune systems also reacted to the vaccine in the same way.
The vaccine is now being modified to contain the strain of HIV most common in South Africa, and by January and 200 more South Africans will be vaccinated with it. But it could leapfrog into a massive R1-billion trial within a year if the people respond according to the Thai trial.
“We have already set our ‘go or no go’ criteria based on the Thai trial and if we meet these, we can go straight into a Phase 3 trial of 7000 people by the end of 2016,” said Medical Research Council President Dr Glenda Gray.
The Thai trial combined two vaccines. The first aimed to prime people’s immune systems to recognise the types of HIV most common in Thailand (sub-types E and B) and the other, injected later, aimed to boost their immune systems to fight infection.
The “primer” vaccine now has to be modified to contain HIV sub-type C, which is most common in South Africa.
Discussions have already been held with the Medicines Control Council to license the vaccine by 2019 if the Phase 3 trial goes well, and also to vaccinate children along with the current HPV vaccine to prevent cervical cancer, said Gray, who added that even if the vaccine only gave 50 percent protection, government would probably still license it.
Given the trickiness of HIV and the diversity of people’s sexual practices, HIV researchers say they want to be able to develop a range of different HIV prevention products – including perhaps a partially protective vaccine.