As resistance grows, malaria vaccine raises hopes

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(IRIN) – Even as researchers announce that a malaria vaccine could be available by 2015, the threat of resistance – by the malaria parasite to the most effective drugs and by mosquitoes to frontline insecticides – continues to grow. Donor funding for malaria has plateaued, and African countries are struggling to finance the scale-up of some crucial interventions.

The Sixth Pan African Multilateral Initiative on Malaria, the world’s largest conference on malaria, took place in Durban, South Africa, this week, where results from the most clinically advanced trials showed that over 18 months of follow-up, the RTS,S vaccine almost halved the number of malaria cases in young children and reduced by about a quarter the number of malaria cases in infants.

Armed with these latest results, pharmaceutical giant GlaxoSmithKline (GSK) “now intends to submit, in 2014, a regulatory application to the European Medicines Agency (EMA),” said GSK, which has spent three decades developing the vaccine.

RTS,S is designed to prevent the malaria parasite from infecting, maturing and multiplying in the liver, after which the parasite would normally re-enter the bloodstream and infect red blood cells, leading to disease symptoms.

Efficacy

The fact that the vaccine is only partially effective, “only tells part of the story, when we look at its public health impact,” David Kaslow, vice president of product development at the health organization PATH, told IRIN. The real story lies in the number of malaria cases that could be averted. About 941 cases of clinical malaria were prevented for every 1,000 children vaccinated, while severe malaria cases were reduced by 36 percent. In addition, malaria hospitalizations were reduced by 42 percent.

The effectiveness of the vaccine has weakened over time. In 2011, researchers found after one year that the vaccine reduced the risk of developing clinical malaria – when the disease requires medical treatment – by 56 percent in young children and 31 percent in infants.

“The [vaccine’s declining] efficacy over time is not unexpected. What we don’t know now is what that means and what will happen in the longer term,” Kaslow noted. Additional results, expected in 2014, will give more information on the longer-term protection provided by the vaccine candidate and on the impact of a booster dose given 18 months after the first three doses of the vaccine.

According to GSK, the World Health Organization (WHO) has indicated that it may recommend use of the RTS,S vaccine as early as 2015 if EMA regulators back its licence application. It will then be up to African governments to decide whether to introduce the vaccine into their public health systems.

But even a moderately effective vaccine could have a huge impact in sub-Saharan Africa, which accounts for about 70 percent of malaria deaths each year – most of them children. Duncan Earle, the director of the Malaria Control and Evaluation Partnership in Africa (MACEPA), told delegates at the conference that when statistics were gathered three years ago, there were 219 million reported cases of malaria infections resulting in the deaths of 660,000 people.

“Approximately half of the world’s population is at risk of [contracting] malaria. Most of the malaria cases and deaths occur in sub-Saharan Africa. However, Asia, Latin America, and, to a lesser extent, the Middle East and parts of Europe are also affected,” he added.

Risks ahead

The conference also heard how “populations of mosquitoes resistant to all available insecticide (including DDT) are being increasingly reported”, raising fears that another 120,000 people could die from the disease every year.

Professor Hillary Ranson of the Liverpool School of Tropical Medicine warned that the impact of insecticide resistance could be “devastating”. With no new anti-malaria insecticides on the horizon, Ranson urged governments in Africa and other malaria belts to monitor insecticide resistance and to rotate the variety of insecticides used to reduce the spread of the disease.

Global funding for malaria, however, has reached a plateau well below the level required to reach the health-related Millennium Development Goals and other internationally agreed-upon global malaria targets.

An estimated US$5.1 billion is needed for every year between 2011 and 2020 to achieve universal access to malaria interventions in the 99 countries with ongoing malaria transmission. While many countries have increased domestic financing for malaria control, the total available global funding remained at 2.3 billion in 2011 – less than half of what is needed.

Malaria kills about 660,000 people a year worldwPhoto: Wendy Stone/IRINide
Malaria kills about 660,000 people a year world Photo: Wendy Stone/IRINide

“We also hope that the wealthy countries would not only talk the talk but would also contribute generously to the funds that are aimed at eliminating the disease. At the moment, Africa is facing crises of funding, and we hope that companies would also fund these initiatives,” Elhassan Hassan, a researcher at the University of Gezira in Sudan, said at the conference.

Source- IRIN

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