One might think that the first vaccine candidate to protect against malaria as cause of jubilation. But instead, the data on the candidate, known as RTS, S or Mosquirix have dribbled over the past two years, he was greeted with considerable-scratching head and some consternation about whether and how use.
The problem is that the vaccine developed by pharmaceutical giant GlaxoSmithKline (GSK), in partnership with the PATH Malaria Vaccine Initiative, does not work very well. In a large phase III trial, it reduced malaria episodes by about one third among young children in sub-Saharan Africa. That's well below the 50% efficiency expected at the beginning of the trial, and a far cry from the 95% efficiency of the dream vaccine manufacturers, leaving scientists and policy makers asking: What is good enough
part of the answer came today, as the European medicines Agency (EMA) has approved the use of the vaccine in African children aged 6 weeks to 17 month. The movement is a key first step on the way potentially complicated the deployment of the vaccine in sub-Saharan Africa. According to the fastest scenario, however, the introduction will not begin until 2017.
"We are very pleased with the outcome, said Moncef Slaoui, GSK vaccine president who for 30 recent years has been working alongside Joe Cohen and others to develop the vaccine. "the health of children in Africa will be transformed," he predicted.
But ask a malaria expert on what to do with RTS, S and they will tell you "it's complicated" There is no doubt that the vaccine candidate is a great achievement. Nobody never developed a vaccine against a parasite, especially one as cunning as Plasmodium falciparum , the main cause of malaria in Africa. And malaria is a huge problem, claiming nearly 0,000 lives a year , mostly children in sub-Saharan Africa. new tools to reduce the number of victims of malaria are desperately needed.
at the same time, everyone, including scientists at GSK wants some something better from a vaccine. at the end of the multicellular RTS, S trial, which involved all 16,000 children in eight African countries, the vaccine reduced malaria cases by 39% in young children 5 to 17 months and 27% for infants 6 to 12 weeks. Because vaccine efficacy decreases with time, trial tested three doses delivered 1 month apart, followed by a booster 18 months later.
"positive scientific opinion," The EMA as it is clumsily called, essentially concludes that the benefits outweigh the risks of using the vaccine in two age groups. The opinion is not a recommendation for use or formal approval is for countries to decide, but it opens the way to the World Health Organization (WHO) to make an overall recommendation on whether and how to use the vaccine. WHO should issue this recommendation by the end of the year.
The EMA review is part of an arcane regulatory process known as Article 58. As a service to poor countries that might not have the scientific expertise, the Committee of agency of human medicines reviewed the evidence in this case scientific hundreds of thousands of pages-with the same rigor as it would be in the review of a drug to be marketed in the European Union.
Then, in his review, WHO will address issues such as the real world cost-effectiveness, feasibility and public health value of the vaccine compared with other interventions. The result could go many ways. For example, WHO might recommend the use of the vaccine in all African countries affected by malaria only in areas where transmission is high. It could only recommend its use in toddlers whose effectiveness was higher, or in infants as well.
A second WHO committee decide whether the vaccine meets international standards of quality and safety and efficiency.
As with the EMA, the WHO recommendations are not binding, but poor countries the resources usually follow. And donors like GAVI Alliance vaccine, will not pay for the vaccine in poor countries without this recommendation.
Ultimately, it is up to regulators in each country to decide whether to approve RTS, S. Assuming that the WHO recommends the use of the vaccine, it will be a "difficult decision "for countries with limited resources, says Mary Hamel, an epidemiologist with the US centers for disease control and prevention and one of the principal investigators. David Kaslow, vice president of product development for PATH, agrees. "It is a bit unusual since the vaccine was introduced in the context of other interventions that also have costs associated with them," he said.
If the vaccine is not moving forward, scientists and policy makers agree it should be used only as a complement to other tools in the fight against malaria, such as bed nets and antimalarial drugs, not as a replacement. vaccine funding should not divert more effective interventions and research resources, WHO said today in a statement.
the opinion of the EMA is sure to fuel a debate over whether is preferable to wait a near-perfect vaccine against malaria or do better with what you have. in a comment to the BBC, the head GAVI Seth Berkley and Mark Dybul, head of the global Fund to explore the dilemma. "Mosquirix is about 5 to 10 years ahead of all other vaccine candidates," they write, "and there is no guarantee any of them will be better. "
" With every vaccine, of course you hope for 100% protection, "said Slaoui, GSK and is already working on a second-generation vaccine. But he called the current vaccine protection "substantial". "If your child has three severe malaria a year instead of six, it will change their lives."
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