The complete eradication of malaria from the earth has proved quite herculean for scientists and researchers but eventually the work may be showing results. With several approaches being pointed at how to unleash a severe blow to malaria, one of the world’s deadliest diseases, the development of a vaccine is vigorously being pursued with trials underway.

The first vaccine RTS,S is in its third phase of trial to determine its efficacy and it is currently the world’s most clinically advanced malaria vaccine candidate.

A study participant in the RTS,S vaccine trials in Ghana receiving a shot

About 16,000 children in two age groups – six to 10 weeks and five to 17 months from seven African countries namely, Ghana, Burkina Faso, Gabon, Kenya, Malawi, Mozambique and Tanzania are taking part in the trial.

“Results of the studies as of now have shown that RTS,S is safe and can reduce the risk of clinical episodes of malaria in young children by 53 per cent…” explained Dr Ashley Birkett, Director, Preclinical Research and Development of the Malaria Vaccine Initiative  in a recent interview at the 58th annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) held in Washington DC, USA.

The PATH Malaria Vaccine Initiative (MVI) is a global health organisation working to accelerate the development of malaria vaccines and to ensure that they are available and accessible in the developing world.
 
Depending on the final clinical profile of the vaccine and the regulatory review process, the first vaccine introduction could take place over the next three to five years.
Dr Birkett said eradicating malaria will require that the vaccines being developed are used together with existing interventions such as indoor residual spraying, insecticide treated nets and drug therapy.

PATH MVI also shared its new strategy to develop what it terms “next generation” malaria vaccines at the meeting. The new strategy is to develop a vaccine with the aim of blocking the cycle of malaria transmission between people in a community.

According to Dr Birkett, the transmission-blocking vaccines which is in the early clinical trial stage aims to interrupt the life cycle of the malaria parasite by including antibodies in humans that prevent the parasite from maturing in the mosquito after it bites a vaccinated person.
The transmission-blocking vaccines would not prevent the person receiving the vaccine from getting malaria, but would significantly limit the spread of infection and disease to others.

For instance the MVI is also working with Sanaria Incorporated to develop the malaria vaccine (Sanaria PfSPZ) that uses the approach of a weakened form of Plasmodium falciparum, the parasite responsible for more than 95 per cent of malaria related illness and death worldwide; Sanaria’s PfSPZ malaria vaccine will use a whole-organism approach to target the Plasmodium falciparum.

The Chief Executive Officer of Sanaria, Dr Stephen Hoffman said the vaccine developed for blocking malaria transmission has been found to be safe and is currently being tested in adult volunteers in the United States.

Again, PATH MVI and the United States Agency for International Development (USAID) Malaria Vaccine Development Program (MVDP) are collaborating with the Dutch biopharmaceutical company Crucell N.V. to accelerate the development of a promising type of malaria vaccine. The partners will conduct studies to determine the effectiveness of Crucell’s prime-boost vaccine approach on the malaria parasite Plasmodium falciparum.

This approach uses adenoviruses (a type of virus associated with the common cold and other minor respiratory infections) to deliver a malaria antigen to the immune system.

“The malaria community has made impressive strides in reducing deaths in the last ten years, but malaria still incurs a crushing global burden. History has shown us that a vaccine would add a powerful, cost-effective way to save lives and help eliminate this disease,” said Dr Christian Loucq, Director of MVI.

He said MVI’s new strategy to develop “next generation” malaria vaccines “will build, efficiently and aggressively, on the incredible knowledge generated in MVI’s first decade of operation.”

As the number of potential malaria vaccine candidate increases, scientists will need new and better technologies to assess their potential efficacy and decide which should go forward.

According to MVI, it is supporting the refinement and development of both laboratory tools and methodologies for evaluating vaccine candidates in humans. For instance, MVI is supporting development of the Human Challenge Centre at the Seattle Biomedical Research Institute which will this year offer early stage testing in humans of the safety and efficacy of malaria vaccine candidates.

The success of the development of the malaria vaccines to a large extent also involves funding and malaria experts who attended the ASTMH meeting used the opportunity to call on the US government to increase funding for malaria programmes, which will focus on developing new anti-malarials and vaccines at a briefing on Capitol Hill.

Dr Kent Campbell, the Director of PATH’s Malaria Control Programme in Africa, said eliminating malaria will take decades and success will not be possible without consistent investment in the development of improved tools for controlling malaria. “Recent progress has emboldened the malaria community to speak of malaria elimination and eradication, and plans have been developed to make this long-term aspiration a reality,” he said.

Dr. Campbell explaining a point

Dr Campbell said drug and insecticide resistance was a reality and there was the need for a vaccine that could block infection adding that “if we do not invest in these programmes to develop treatment and prevention, there will be devastating effects on the progress made thus far.”

Adding her voice to the appeal for increased funding for malaria, Dr Patricia W. Njuguna, of the KEMRI-Wellcome Trust Research Programme in Kenya and a Principal Investigator in the RTS,S vaccine trial said “as a pediatrician working near the coast of Kenya, where malaria still persists despite rollout of current prevention methods, I regularly see the tragedy of young children dying of the disease and the grief of parents who couldn’t protect them. My hope is that the international community will be ready to support the availability of this vaccine, if approved, so that the children of Kenya and other African countries will have access to it as soon as possible. There are lives to be saved.”