Safety net (Image: Ton Koene/Visuals Unlimited/Corbis)
A disease that kills around 1300 children each day in sub-Saharan Africa may shortly be on the run, thanks to promising results from what could become the world’s first vaccine against malaria – and the first against a parasitic disease.
Developers of the vaccine are hopeful that in the wake of the results, it will receive official clearance for use by the end of the year. However, it could be next year or later before the vaccine clears regulatory hurdles in individual African countries.
Although the protection is modest, four jabs of the RTS,S vaccine reduced cases of malaria in children aged 5 to 17 months and babies aged 6 to 12 weeks at first vaccination by 36 and 26 per cent respectively after four years, compared with non-recipients.
“Given that there were an estimated 198 million malaria cases in 2013, this level of efficacy potentially translates into millions of cases of malaria in children being prevented,” says lead author Brian Greenwood of the London School of Hygiene and Tropical Medicine.
“The critical thing is learning how to use an imperfect vaccine like this most effectively,” he says. Because the success of the vaccine turned out to be roughly the same in areas of low and high transmission, programmes could be more worthwhile in high-transmission areas where more children are at risk, for example.
Developed through a partnership between the PATH Malaria Vaccine Initiative in Washington DC and the pharmaceutical company GlaxoSmithKline (GSK), RTS,S was tested in 15,459 children in seven African countries where malaria is commonplace.
Recipients were divided by age into babies aged between 6 and 12 weeks, and children aged between 5 and 17 months, to see the age group in which vaccinations would work best. All children received three jabs within two months, and some also received a booster dose 18 months later.
The results show that the vaccine worked best among the older children when they also received the additional booster dose, reducing cases over four years by 36 per cent. This figure fell to 28 per cent if they didn’t receive the booster. Earlier, interim results at 14 months had shown that cases in these children halved, so the latest figures show that the protective effect wanes with time.
In babies, cases were reduced by 26 per cent in booster recipients compared with 18 per cent in non-recipients. The booster also provided better protection against severe malaria in the older children, but not in the babies.
The same pattern of the older children gaining better protection than babies was also seen earlier in the trial. This could be down to several factors, including the relative maturity of the age groups’ immune systems, or interference from other vaccines given at the same time and antibodies passed down from mothers.
Now that the results are in, regulatory bodies around the world are preparing the ground for approval. The European Medicines Agency (EMA) is assessing GSK’s submission to have the vaccine approved, and is expected to decide in September.
In anticipation of that, the World Health Organization (WHO) has assembled a panel that will meet in October to decide whether to make RTS,S jabs routine for children in Africa. “We’ve established a specific, expedited review process for this vaccine,” says Vasee Moorthy of the WHO’s vaccines department in Geneva, Switzerland, who also wrote an accompanying commentary in The Lancet.
“Our decision will be made available as early as a month after the EMA’s regulatory decision is known,” he told New Scientist. A spokeswoman for GSK said that even if the EMA and WHO approve the vaccine, it could take another year or two to be given the green light in individual African countries.
Moorthy, meanwhile, warned against funding a huge new vaccination programme at the expense of other measures against malaria that have proved effective – such as providing insecticide-treated bed nets to protect sleeping children against mosquitoes that carry and spread the malaria parasite, Plasmodium falciparum, in their blood.
“Any possible use of this vaccine in the future must take place in the context of the WHO’s recommended core malaria-control measures, prioritising universal access to long-lasting insecticidal nets and prompt access to diagnosis and treatment with artemisinin-combination therapies,” he told New Scientist.
Moorthy also warned that the development of other anti-malaria vaccines, including one isolated from mosquito spit, is “at least 10 years behind” – so RTS,S is the only existing vaccine hope for a decade or more to come.
By: Andy Coghlan