Reflections on the AIDS conference in Durban

Aug 11, 2016

This reality was the focus of some 18,000 delegates who attended the 21st International AIDS Conference, which took place last week in Durban, South Africa between July 18-22.

Around 78 million people have become infected with HIV and almost half of them have died from AIDS-related illnesses since the epidemic started 35 years ago. This year, estimates say that more than 2 million people will become infected despite advances in prevention and treatment, a tragic toll that has stubbornly remained about the same over the last six years.

This reality was the focus of some 18,000 delegates who attended the 21st International AIDS Conference, which took place last week in Durban, South Africa between July 18-22. What were the overarching findings that came out of the event? That the world has entered a fragile period in the effort to reverse and eventually end the global AIDS epidemic.

With 17 million people now on antiretroviral treatment around the world and AIDS-related mortality declining, delegates heralded significant progress in providing treatment to people living with HIV. Success is also clear in the drop in mother-to-child transmission—some countries are very close to eliminating this pathway, thanks to advanced drug regimens. Still, more than half of the nearly 37 million people who are HIV positive do not have access to treatment, and prevention measures like condoms, PrEP (pre-exposure prophylaxis) and male circumcision are being employed far too rarely. A major study released during the conference determined that 74 countries saw increases in new infection rates between 2005 and 2015. Such findings led a number of researchers, policymakers and advocates to flatly tell delegates that global prevention efforts are failing.

The data and public comments by the world's leading researchers on the subject became clear as the event's end neared: we are not going to end AIDS with the tools we presently have at hand. In separate talks, at least a dozen scientists and policy experts said that to truly end HIV/AIDS will require an effective cure to clear the virus from infected patients and a vaccine to prevent infection from ever starting.

During Durban, those looking for a cure said they are still trying to understand exceptional cases—one of a baby in Mississippi, another of an adult in Berlin—where treatments permanently or temporarily cleared all signs of HIV from the blood. The biggest barrier to a breakthrough is getting past what is called viral latency, where HIV hides out in the body sheltered from immune system attack. But research presented at the conference showed hopeful signs in overcoming this obstacle. Stem cell, gene-editing and combination antiretroviral therapies all offer potential pathways to clear HIV from infected people. And pediatric HIV researchers are now investigating starting infected babies on antiretroviral therapy 48 hours after birth to diminish the viral load and its impact.

On the vaccine development front, much of the recent interest has evolved from the surprising efficacy of an experimental vaccine called RV 144 performed in Thailand. The findings from this trial, released in 2009, showed the vaccine offered 61% of HIV negative people who received it immunity for the first year. Immunity held for 31% of those vaccinated for more than three years.

This was an exciting advance that revealed it is possible to prevent HIV infection by harnessing the immune system pre-exposure. In South Africa, interim immunology results reported in Durban have opened the way for the first major vaccine efficacy trial in seven years. This follow up clinical trial to RV144, identified as HVTN 702, will begin enrolling participants in South Africa by the end of 2016 to see if researchers can prolong the immune response from the modified vaccine.

The next major multi-site efficacy trial led by J&J is likely to test a vaccine regimen including a ‘mosaic' immunogen carrying fragments of HIV from different variants of the virus. Researchers, including from IAVI, believe that this complex immunogen might be fit for use globally, regardless of virus variants.

Meanwhile, scientists are investigating a number of approaches that could prove useful to prevent infection. One showing particular promise harnesses broadly neutralizing antibodies, which can effectively recognize and target multiple strains of HIV. Others are working to employ HIV's own DNA and envelope proteins to block it from infecting people. With these developments, the preventive vaccine development community now believes that a potent and effective vaccine is possible. It is a significant change of heart by many who once thought HIV was just too cunning of an enemy.

Yet at a moment of rising hope, another study found that 13 of 14 donor governments had reduced their funding for AIDS programs in low- and middle-income countries. Overall public and private sector funding both decreased in 2015. This is particularly troubling given that Africa, the epicentre of the epidemic, is seeing the beginning of a "youth bulge" that has emerged as HIV/AIDS reduced lifespans dramatically. As highlighted at AIDS 2016, young women in sub-Saharan Africa are particularly vulnerable to infection and in dire need of more effective tools of prevention. Research shared at the conference by the Centre for the AIDS Research Programme in South Africa (CAPRISA) provides new information on the drivers high rates of HIV infection in young women and on two vaginal bacteria - one which increases HIV vulnerability and another which undermines the efficacy of tenofovir-based topical PrEP.

What is clear from the presentations and discussions at AIDS 2016 is that the world cannot let its foot off the accelerator powering efforts to end the epidemic, especially for future generations. Without renewed funding for treatment and to advance international vaccine and cure development efforts, a backslide in the global fight against AIDS is a very real possibility.   

Released by IAVI, The International AIDS Vaccine Initiative, which is a nonprofit organization working to accelerate development of broadly effective AIDS vaccines accessible to all.

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