New data has confirmed the high efficacy of a malaria vaccine partly being tested in Kilifi.
Trial investigators reported on average 78 per cent vaccine efficacy over the first year of follow-up in Kilifi and four other sites in Burkina Faso, Mali and Tanzania, where tests are also ongoing.
The results relate to children aged five to 17 months, the age range which is studied for most malaria vaccines.
The full results of the Phase III trial have been published in the Lancet journal.
“No other vaccine has reported over 55 per cent efficacy in the same age group,” said a statement from the researchers, who include Dr Mainga Hamaluba, the principal investigator in Kilifi.
The vaccine is known as R21/Matrix-M.
Its 78 per cent efficacy means that if 100 children were vaccinated and exposed to the malaria parasite, approximately 78 of them would be protected from getting sick, while 22 might still contract malaria despite being vaccinated.
The researchers also reported no serious adverse events linked to immunisation.
“R21/Matrix-M vaccine was well tolerated, with injection site pain and fever as the most frequent adverse events,” they said.
“Number of adverse events of special interest and serious adverse events did not significantly differ between the vaccine groups. There were no treatment-related deaths.”
One group of children received the test vaccine while the control received a rabies vaccine.
In Kilifi, 600 children were involved in the study, but overall, more than 4,800 young children took part in the trial in the four countries.
The Ministry of Health estimates that approximately 4,000 people in Kenya die from malaria every year, most of them being children.
The R21 was approved by the World Health Organization in December last year.
It comes after the RTSS malaria vaccine, also partly tested in Kenya, which offers modest protection and is already being given to children in Western Kenya.
R21 was designed in 2011 as a potential improvement on the RTSS vaccine designed in the 1980s.
It was developed by the Oxford University of the UK but will be manufactured by The Serum Institute of India (SII), the university said in a statement.
Prof Adrian Hill, chief investigator of the entire trial, said: “The continued high efficacy of this new vaccine in field trials is very encouraging and consistent with the high efficacy and excellent durability observed in a smaller four-year phase IIb trial.”
SII, the world’s largest vaccine manufacturer, said they are ready to deliver 100 million doses a year.
Adar Poonawalla, CEO of the company, said: “We are dedicated to making this vaccine available, especially in Africa, where malaria poses a substantial threat to millions of lives, bringing us closer to a malaria-free world."
Ghana, Nigeria, and Burkina Faso have already approved the jab for use, while Kenya said it could approve it this year.
Several scientists also gave their assessment of the results.
Prof Eleanor Riley, an immunologist from the University of Edinburgh, said it could play a key important role in reducing the burden of malaria in children. “There is however, one important caveat. None of the five sites in the study represents an area of intense, perennial malaria transmission such as is seen – for example – in central Africa. This is the ultimate test of any malaria vaccine,” Prof Eleanor said.
She said although the R21 vaccine is a re-engineered version of the existing RTSS, it benefits from a higher ratio of the active ingredient that induces the body’s immune response.
It is also combined with a modified adjuvant, a substance which enhances that immune response.
“This may explain the apparently higher immunogenicity of R21 compared to RTS,S but as the two vaccines have not been tested against each other in head-to-head studies it is not possible to directly compare the two vaccines. R21 seems to be able to be manufactured at larger scale (and lower cost) than is currently the case for RTS,S,” she said.
According to WHO, it will cost $2 to $4 per dose.