Accelerating the era of HIV vaccination

Accelerating the era of HIV vaccination

By Linda-Gail Bekker, International AIDS Society President

Vaccines are modern miracles. Every year, vaccines save up to 3 million lives worldwide [1]. The measles vaccine alone has saved more than 20 million lives since 2000 [2]. Smallpox, a disease that as recently as the 1960s was associated with a death toll comparable to HIV, has now been eradicated as a result of vaccination efforts. Immunization programmes are on the cusp of eliminating polio, and expanded use of the hepatitis B vaccine is contributing to reductions in the global burden of that disease as well [3].

In the case of HIV, no preventive vaccine is currently available. But we have come a very long way in the search for an HIV vaccine, with a rich research and development pipeline that now includes an array of approaches to HIV immunization.

My own involvement in HIV vaccine research began in 2004 when we did the first community-based “willingness to participate” studies. Gratifyingly, we discovered that communities in South Africa believe in vaccines and have great hope for an effective HIV vaccine. Although the earliest vaccine research did not yield an effective vaccine, these efforts left us with lessons and insights that have proven invaluable in the search for an effective vaccine.

Indeed, there are signs that we might soon see a light at the end of the tunnel. In 2009, a clinical trial in Thailand confirmed for the first time that a vaccine could prevent HIV infection. Currently, I am serving as Co-Chair of HVTN 072 together with Dr Glenda Grey (Chair); this is a large efficacy trial in South Africa of a vaccine that is evaluating what we hope is an improved version of the vaccine tested in the Thai trial. One of my sites is also involved in one of a series of studies evaluating whether intravenous infusions of HIV antibodies can protect against HIV acquisition.

In my many years of HIV vaccine research, I’ve learned a lot about what makes a successful vaccine trial. In particular, community engagement and support is an essential building block for successful research. In South Africa, communities are thirsting for an HIV vaccine and are ready to put to use a vaccine proven to be safe and effective. Given the grassroots enthusiasm for new methods to prevent HIV infection, people are eager to enrol in vaccine research in South Africa. And communities have actively stepped forward to promote and support these HIV prevention trials.

The worst possible outcome for a large, expensive Phase III efficacy trial is a set of results that are ambiguous, unclear or difficult to interpret. That’s why such care and thought goes into the design and roll out of a Phase III trial. The past several years have seen an exciting expansion of HIV prevention options, but this has paradoxically made vaccine trials more difficult to design. Our studies offer all participants access to PrEP – an ethical imperative, but one that complicates efforts to compare the experimental vaccine arm of the trial with a control group. This means that innovation in the design of new trials will be critical as we move forward in our search for an effective HIV vaccine.

For those of us who have witnessed the highs and lows of our quest for a preventive vaccine, these are exciting times. But we aren’t there yet, and there is a real risk that long-term commitment to finding a vaccine could wither over time. We must not allow that to happen, as a preventive vaccine will likely be essential for ending the HIV epidemic once and for all.

It is our hope that through the recently announced partnership between the International AIDS Society (IAS) and the Global HIV Vaccine Enterprise, we will foster new collaborations between the HIV vaccine community and the broader HIV community to work towards our common goal of accelerating the era of HIV vaccination.

Not that long ago, many leading scientific experts questioned whether a vaccine against HIV was even feasible. We now know that the potential for HIV vaccination is real. We must now redouble our efforts and be smart in our choices, so that we reach the ultimate finish line in our fight against HIV.