Hopes that the world will finally be able to immunise people against malaria received a shot in the arm this week as leading health experts unveiled the blueprint for a preventive vaccine in the Thai capital, Bangkok.
Yet, the architects of this new global strategy — titled the Malaria Vaccine Technology Roadmap and launched on Wednesday at the end of a three-day conference — warn against too much optimism.
Scientific caution was written all over Dr Carlos Morel, director of the Rio de Janeiro-based Centre for Technological Development in Health. “We know a vaccine is possible, but in reality we are still on the floor with blind eyes. This is a failure of science,” he said in an interview.
The challenge faced by the medical and scientific community stems partly from the nature of the causative parasite, which is unlike other organisms that cause infectious diseases. “Until now, we don’t have a vaccine against parasites; only against bacteria and viruses,” Morel said. “The malaria parasite is very smart.”
In addition, the search for a malaria vaccine has also been hamstrung by funding shortages, because it is largely a killer in the developing world while the general focus of research and funding is on diseases that afflict the developed world.
“It is a disease that doesn’t take place in the United States and Europe and that is where lot of funding for research and development comes from,” said Dr Regina Rabinovich, director of the infectious disease global health programme at the Bill and Melinda Gates Foundation, the Seattle-based entity that is a leading funder for a malaria vaccine.
“It is not a global priority, because it does not have the market drivers,” she added. “It depends on public-sector funding.”
Participants at the international health conference took stock of the progress made to produce vaccines for HIV/Aids, dengue, a pandemic from influenza and cervical cancer, in addition to malaria.
The successful trials for a malaria-vaccine candidate in Mozambique has emerged as the front runner out of a number of possible vaccines on trial, some of them still at a preliminary phase. “We have a malaria-vaccine candidate that showed discernible impact in a trial in Mozambique,” said Rabinovich. “It is a leading candidate for phase-three trials. It is the most advanced.”
But against such hope are two other trials that proved futile after having given initial reasons for optimism. “There were two vaccine studies reported a month ago that showed negative results,” Rabinovich revealed. “These were trials conducted in Africa and the US. These were disappointing, because they were credible candidates for evaluation.”
Ambitious targets
Despite such drawbacks, the road map unveiled this week has set 2025 as a deadline to develop a malaria vaccine that “would have protective efficacy of more than 80% against clinical disease and would provide protection for longer than four years.”
Part of this blueprint — which has the initial support of 230 experts from 35 countries, ranging from the medical and scientific community to policymakers and funders — has also set an equally ambitious target for 2015. The aim by that year is “to develop and license a first-generation vaccine” that would have “50% protective efficacy against severe disease and death that would last longer than one year”.
“Having a highly protective malaria vaccine and putting it into widespread use in affected areas would be a true achievement for public health. It would fulfill an urgent need,” said Dr Marie-Paul Kieny, director of the Initiative for Vaccine Research at the World Health Organisation (WHO). “The road map marks the first concerted global attempt at mapping put a shared plan of action.”
According to a WHO background note, the road map is the product of more than two years’ worth of work by representatives from 100 organisations that are involved in the fight against malaria. Besides the scientific unknowns and limited funding, other challenges this malaria initiative faces are “limited private-sector involvement and uncertain mechanisms for procuring and distributing a successful vaccine”.
“Currently, there are more than 30 potential vaccine candidates under development — far more than there is capacity or funding to investigate in clinical trials, especially in endemic countries,” adds the WHO, one of the organisers of the conference. “The road map puts into motion a strategic plan for aligning research and for developing and making available a safe, effective and affordable vaccine to prevent malaria in children under five years of age.”
The road map has spelled out four areas for action:
- standardising research, using state-of-the-art technology and information sharing;
- vaccine development;
- building good clinical practices in malaria-endemic areas; and
- seeking political and funding support for the programme, including “developing novel regulatory strategies to expedite the approval of a safe vaccine”.
This new strategy comes at a time when malaria continues to leave a deadly trail in countries across the developing world, with those in Africa the most affected. Nearly half a billion people are infected by this mosquito-borne killer disease and close to 1,2-million people die every year from it, 90% of them children under five years and mostly in sub-Saharan Africa, according to the WHO.
“A malaria vaccine has long eluded us. However, the malaria-vaccine community aims to develop and license a product that is both highly protective and lasting by 2015,” said Kieny, of the Geneva-based health agency. — IPS