Developing-world disease vaccines being prepared for human tests

Researchers carrying out a field study on leishmaniasis and malnutrition in children in Amhara State, Ethiopia. Image courtesy of Dr Javier Moreno, Instituto de Salud Carlos III, Madrid, Spain.
Researchers carrying out a field study on leishmaniasis and malnutrition in children in Amhara State, Ethiopia. Image courtesy of Dr Javier Moreno, Instituto de Salud Carlos III, Madrid, Spain.

The fight against poverty-related diseases is gaining ground as scientists prepare trials of vaccines for hookworm, leishmaniasis and other parasitic diseases common in the developing world, thanks to the support of public research funding.

The problem has been that developing countries harbour most of the planet’s chronic diseases, but attract only a small share of its research funding.

That’s mainly because pharmaceutical companies require high returns to justify bank-busting research investments, but victims of poverty-related diseases can rarely afford to pay for patented medicines.

But the anaemia and stunted growth caused by parasitic infections keeps adults away from work, children out of school, and leaves economies on their knees.

That is why the EU is investing in research projects that fund early stage research and clinical trials, offering a chance for the private sector to exploit the results in later-stage development and marketing.

Success could improve close to a billion lives and support economic growth in countries held back by poor health.

The EU-funded HOOKVAC project, for example, is aiming to complete initial human tests on a vaccine for the parasite hookworm.

Project coordinator Dr Remko van Leeuwen, from the Amsterdam Institute for Global Health and Development, sees multiple advantages in this approach. 

‘This is a disease that affects an awful number of people, it’s about 600 million people who are affected by this disease, he said. ‘We believe that a vaccine can really be effective and make a difference.’

‘This is the first time that we are testing a vaccine for a parasite,’ he said.

The vaccine that his team is developing through the HOOKVAC project targets primarily local populations in endemic countries, but Western travellers could also benefit from its results. ‘And the companies that partner with us are European start-ups,’ he added.

Prevention better than cure

Diseases like hookworm and leishmaniasis can be treated by using antibiotics, but that does nothing to prevent reinfection.

‘A few years ago, we didn’t even know the DNA sequence of the schistosome … Today we already have prototypes that reduce worm numbers in animal test subjects.’

Dr Ron Hokke, Coordinator, TheSchistoVac

That makes vaccines both more affordable and more effective, according to Professor Giuseppe Pantaleo, who coordinates the EU-funded IDEA consortium, which examines the links between worms and diseases like tuberculosis, HIV and malaria.

However, vaccines must overcome the intrinsic complexity of many poverty-related diseases. ‘These pathogens change so rapidly that classic techniques are of little use,’ said Prof. Pantaleo, who is based at the University Hospital of Lausanne in Switzerland.

For example, the parasite behind leishmaniasis, a disease that causes sores of the skin, sabotages the standard response of the immune system by infesting the very cells that the body sends out to contain it. It then continues to change form so as to evade antibodies and thrives inside the immune system.

That's why scientists at the EU-funded MuLeVaClin project have worked out a way to engineer agents that are complex enough to keep the parasite in check.

But no matter how clever the technology is, researchers need money to run field tests so they can prove it works. ‘Until now, there has never been funding to find out,’ said Dr Javier Moreno, of the MuLeVaClin project, which is developing a vaccine against leishmaniasis at the Instituto de Salud Carlos III in Madrid, Spain. Thanks to the EU funding, the team expects to run human trials within the coming four years.

Dr Ron Hokke, at the Leiden University Medical Center in the Netherlands, is working on a vaccine for the anaemia-causing disease schistosomiasis as part of the EU-funded project TheSchistoVac. He believes that the goal is challenging, but achievable. ‘A few years ago, we didn’t even know the DNA sequence of the schistosome (the parasitic worm that leads to schistosomiasis),’ he said. ‘Today we already have prototypes that reduce worm numbers in animal test subjects.’

Success depends on many factors: the engineering of the vaccines, the efficiency of inoculation campaigns, and the capacity of the disease to adapt. However, these projects show that the fightback against poverty-related diseases has begun in earnest.

Partnerships to fight developing-world diseases

The EU is also supporting the European and Developing Countries Clinical Trials Partnership (EDCTP), a Europe-wide effort to tackle diseases of the developing world that unites 14 participating EU Member States plus Norway and Switzerland with sub-Saharan African countries.

The EDCTP was launched in 2003 under the EU’s 2002-2006 funding round to support research into the three main poverty-related diseases: HIV/AIDS, malaria and tuberculosis.

However, under Horizon 2020 it is being expanded to cover so-called neglected infectious diseases as defined by the World Health Organization, which includes leishmaniasis and schistosomiasis.

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