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African scientists should lead in developing an Aids jab for Africa

Monday November 29 2021
HIV vaccine.

We need a vaccine that is fit for purpose, culturally suitable and scalable. ILLUSTRATION | JOHN NYAGA

By ANATOLI KAMALI
By EUGENE RUZAGIRA

Scientific progress over the past four decades in the response to the HIV/Aids pandemic has been nothing short of extraordinary. Combination antiretroviral therapy has transformed the disease form a death sentence to a chronically manageable disease.

Some 26 million people around world are now on lifesaving antiretroviral treatment, two-thirds of them from the African continent. Yet each year some 1.5 million people are newly infected with the virus and another 10 million are still failing to access treatment. The cost of maintaining so many people on treatment, at $50 billion going forwards, is also unsustainable in the long term

To end HIV/Aids we need a vaccine.

It’s an irony of science that while much of the research undertaken over the past for decades in the name of an Aids vaccine was so instrumental in the design of the highly effective SARS-CoV-2 vaccines, a fit for purpose Aids vaccine has proved extremely elusive.

At the same time, it’s also true that the extraordinary rapid pace of vaccine development in response to the Covid-19 pandemic has regenerated optimism in the Aids vaccine field.

But we need a vaccine that is fit for purpose, culturally suitable and scalable.

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For many years, the HIV vaccine clinical trials conducted in Africa were almost unanimously led by researchers outside Africa, and while the participation of local volunteers was needed and input from African principal investigators sought, it was standard practice to ship out samples and conduct analysis and interpretation of results elsewhere.

But things are quite different today than in 1999 when the first HIV vaccine clinical trial in Africa was conducted in Uganda. Decades of partnership building and investment in African researchers, institutions and scientific leadership have helped the local capacity for HIV vaccine research to flourish where it has always been needed most — and the hard work is paying off. A case in point is an African-led, multi-site HIV prevention study known as PrEPVacc, currently running across Uganda, Tanzania, Mozambique and South Africa

With oral pre-exposure prophylaxis (PrEP) becoming a global standard of HIV prevention, PrEPVacc is the first vaccine trial that is evaluating PrEP alongside HIV vaccine candidates.

The study is assessing two different experimental HIV vaccine combinations for the prevention of HIV infection, while at the same time, evaluating whether a new formulation of the drugs used for PrEP (Descovy: tenofovir alafenamide, TAF, plus emtricitabine, FTC) is as effective as the current formulation approved for PrEP (Truvada: tenofovir disoproxil fumarate, TDF, plus FTC).

The PrEPVacc trial is also innovative in another way: it has an adaptive trial design which allows for the evaluation of multiple vaccine regimens concurrently and includes early evaluation with the possibility of discontinuing unpromising vaccine combinations.

If one of the lessons of vaccine development has been the need for constant innovation, the other surely has been the importance of ultimately providing an efficacious vaccine that is fit for purpose for the people who need it, that its delivery and rollout are both culturally sensitive and locally appropriate. Vaccine preparedness is everything and local infrastructure is key.

PrEPVacc has tapped the significant potential of HIV prevention research that exists on the African continent. It is the culmination of more than two decades of focused investment to mentor, train, and equip African researchers to not only actively engage in but lead the development and testing of novel HIV vaccine candidates. While it’s supported by European and US partners and funded by the EDCTP, the trial database, trial management, and primary laboratory analyses are, and will continue to be undertaken by African investigators.

In many ways, this is a full circle moment. Equipped with the necessary laboratory, clinical, and bioinformatic capabilities, the lead African researchers in PrEPVacc, world-class experts in their own right, are now mentoring the next generation of African HIV vaccine leaders.

Researchers starting their career paths need look no further than the lauded institutions that already call Africa home, such as the MRC/UVRI and London School of Hygiene and Tropical Medicine Uganda Research Unit; the Mbeya Medical Research Centre in Mbeya, Tanzania; and the HIV Prevention Research Unit in Durban, South Africa.

Perhaps more significantly, this study demonstrates value in prioritising research that can contextually respond to Africa’s realities, by drawing on the intimate understanding of local researchers in the socio-economic context of the populations for whom the research is being undertaken. This sets an important precedent in the region: to champion African solutions by African scientists for Africans — and that is game changing.

Dr Anatoli Kamali is the regional director for East Africa at IAVI. Eugene Ruzagira is an assistant professor of Epidemiology at London School of Hygiene and Tropical Medicine (LSHTM) and leads the HIV Epidemiology and Intervention Programme at MRC/UVRI and LSHTM Uganda Research Unit.

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