IAS calls for stepping up HIV vaccine R&D after PrEPVacc halts its vaccine arm

 PrEPVacc announced today that it "has stopped further vaccinations as there is little or no chance of the trial demonstrating vaccine efficacy in preventing HIV acquisition". Its pre-exposure prophylaxis (PrEP) trial is set to continue.

While IAS – the International AIDS Society – is disappointed at this outcome, we believe that this provides us with lessons to drive HIV vaccine research and development (R&D) with urgency.

“We cannot and will not lose hope that the world will have an effective HIV vaccine that is accessible by all who need it, anywhere,” IAS Executive Director Birgit Poniatowski said. “A vaccine remains one of our most powerful tools to reach and change the lives of vulnerable communities and key populations in the most affected parts of the world.” 

PrEPVacc, an African-led, European-supported HIV prevention study, has been running in four sites in Uganda, Tanzania and South Africa since 2018. With 1,513 participants (men and women aged 18-40 years), it has been testing two experimental vaccine combination regimens to protect against acquiring HIV and a new form of PrEP. 

The PrEPVacc sites are in eastern and southern Africa, the region most heavily impacted by HIV. It is home to almost 21 million of the 39 million people living with HIV globally: 500,000 people in the region acquired HIV in 2022, and 61% of them were women and girls.

HIV prevention is often approached through a combination of methods, including condoms, antiretroviral therapy (ART) and behavioural interventions. A successful HIV vaccine could provide long-term protection with a single or limited number of doses, simplifying adherence and reducing the need for ongoing interventions. 

A vaccine could help reduce the stigma associated with HIV by normalizing prevention practices. Importantly, it could ease the burden on key populations, including gay men and other men who have sex with men criminalized by some of the world’s harshest anti-gay laws in parts of the PrEPVacc study region. 

An HIV vaccine could alleviate healthcare costs and contribute to the economic well-being of communities in affected regions. Also, the pursuit of an HIV vaccine drives scientific innovation and contributes to our understanding of the immune system and infectious diseases: a case in point is the rapid development of vaccines for COVID-19, which drew heavily from HIV vaccine research. 

At the IAS, we believe that even when efficacy studies have not shown the desired outcomes, they offer valuable lessons and data that researchers can use to refine their approaches. Understanding why certain strategies are unsuccessful is crucial for making informed adjustments and moving us closer to an effective vaccine. 

The IAS is committed to ending HIV as a threat to public health and individual well-being, and we call on all stakeholders, including in Europe, to step up HIV vaccine R&D to make that a reality.   

Europe must not abandon the quest for an effective HIV vaccine

 On this HIV Vaccine Awareness Day, IAS – the International AIDS Society – calls for the re-engagement of all stakeholders, especially in Europe, in funding HIV vaccine research and development (R&D). 

After more than 40 years since HIV was discovered, there have been breakthroughs in curbing acquisition through pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART). However, 1.5 million people acquired HIV in 2021 – one million above the 2020 global targets for ending the AIDS epidemic – and a quarter of the 38.4 million people living with HIV globally do not have access to treatment. A vaccine remains the most effective prevention method and is still elusive.  

Between 2019 and 2020, funding globally for HIV preventative vaccine R&D decreased by 5.5% or USD 46 million. In comparison, European funding decreased by 31%, significantly undermining pathways to an effective vaccine. 

“We call on Europe to not abandon the quest for an effective HIV vaccine. The role of an effective HIV vaccine in the global HIV response cannot be underestimated, especially in low- and middle-income countries where HIV prevalence is still high,” Marlène Bras, IAS Director, HIV Programmes and Advocacy, said. “An effective and accessible vaccine will make it much more likely that we will meet our global targets.” 

The IAS Global HIV Vaccine Enterprise notes that the goal of HIV vaccine development is to give long-lasting protection with the fewest number of doses, ideally a single dose. Introducing PrEP in 2012 has proven to be an effective prevention mechanism. But it requires consistent use, and inequities in access and stigma linked to taking HIV medication persist.  

An HIV vaccine would save the world billions just in ART provision. Treatment remains expensive relative to a vaccine. In Europe, 2.3 million people are living with HIV, and almost 300 people were diagnosed with HIV every day in 2021; the estimated yearly cost per client is EUR 11,638 in Spain, EUR 32,110 in Germany, EUR 14,821 in France, and EUR 6,399 in Italy.  

Discontinuation of the Mosaico efficacy trial due to lack of efficacy offers lessons to build on, and there is still hope for an HIV vaccine. Strategies being pursued include the induction of broadly neutralizing antibodies and dendritic cell-based immunotherapy. HIV vaccine research played a crucial role in facilitating the development of COVID-19 vaccines. A therapeutic HIV vaccine is feasibly the key to finding a cure with remission of the virus.  

The progress and the intersection of the latest HIV cure and vaccine R&D will be explored in the 2023 HIV Cure & Immunotherapy Forum at IAS 2023, the 12th IAS Conference on HIV Science, in Brisbane, Australia, this July.  

The IAS is committed to ending HIV as a threat to public health and individual well-being, and we call on all stakeholders to commit to funding the development of an HIV vaccine to make that a reality.  

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