A malaria vaccine undergoing trials across Africa show that it reduced the risk of clinical malaria by half in children aged five to 17 months - a result that health experts say confirms its promise as a potentially valuable tool in malaria control.
The results were announced on Tuesday at the Malaria Forum hosted by the Bill & Melinda Gates Foundation in the U.S. city of Seattle and published online in the New England Journal of Medicine.
The large-scale Phase III trial of the RTS,S vaccine was conducted at 11 sites in seven countries across sub-Saharan Africa. It showed that three doses of RTS,S reduced the risk of children experiencing clinical malaria and severe malaria by 56 percent and 47 percent respectively.
The trial is one of the final stages in evaluating the efficacy and safety of the vaccine candidate in infants and young children on a large scale before submitting the vaccine to regulatory authorities for approval of its regular use.
"Today African scientists have shown that persistent scientific inquiry can help us defeat one of the worlds most devastating killers. This 11-site Phase III trial has been conducted in Africa for Africans by capable African scientists," said Christopher Elias, president and CEO of PATH, the Seattle-based Program for Appropriate Technology in Health. "The results made public today are encouraging and certainly something to feel good about, but let's also remember the human dimension."
High fevers and chills characterize clinical malaria. The mosquito-borne disease can rapidly develop into severe malaria that can prove fatal. It is particularly dangerous for children and pregnant women.
Malaria kills nearly 800,000 people a year worldwide and sickens tens of millions more, most of them children living in sub-Saharan Africa.
Health experts say a safe and effective vaccine would be an important component of a comprehensive malaria control program and could potentially save hundreds of thousands of lives.
"A vaccine is the simplest, most cost-effective way to save lives," said Bill Gates, co-chair of the Bill & Melinda Gates Foundation. "These results demonstrate the power of working with partners to create a malaria vaccine that has the potential to protect millions of children from this devastating disease."
The RTS,S malaria vaccine candidate is still under development and currently is the most clinically advanced malaria vaccine candidate in the world.
With the support of the Gates Foundation, RTS,S is being developed in partnership by GSK and the PATH Malaria Vaccine Initiative (MVI), together with prominent African research centers. Should it be approved by regulatory authorities and recommended by the World Health Organisation (WHO), it will be used for African children, who are most at risk from the disease.
"The interim results of this trial confirm the efficacy of this vaccine in infants and older children and take it a further step along the road to becoming the first malaria vaccine to be licensed and used in public health programs," said professor Brian Greenwood of the London School of Hygiene & Tropical Medicine. "We now have confirmation of its promise as a potentially valuable tool in malaria control."
The London School of Hygiene & Tropical Medicine is home to the Malaria Centre, which has the largest number of malaria researchers, students and support staff in Europe. Staff in the UK and Africa have been involved in the development of the vaccine.