[OUAGADOUGOU] Researchers plan to deploy a new vaccine once morest malaria next year following tests on children in West Africa found it to be up to 80% effective.
More than 100 malaria vaccine candidates have been tested in humans over the past decades, but none had previously achieved the World Organization’s goal of more than 75% efficacy. of the health.
Scientists have warned that progress has stalled in the fight once morest this sickness mosquito-borne disease, which caused more than 640,000 deaths in 2020, the majority of them children in sub-Saharan Africa.
“Conducting vaccine trials in Africa assures us that the efficacy of a candidate vaccine at the end of the trial will reflect its performance in the real conditions of its use”
Halidou Tinto, IRSS, Burkina Faso
Researchers from the University of Oxford (United Kingdom) and the Institute of research in Health Sciences (IRSS) from Nanoro in Burkina Fasoclaim that a booster shot of the candidate malaria vaccine, called R21, showed 80% effectiveness in children who received the highest dose one year following an initial three-dose course.
78% efficacy was maintained for two years following the booster was administered in the trial involving 450 children aged five to 17 months at the Nanoro Clinical Research Unit. There were no serious side effects, say the researchers.
Halidou Tinto, regional director of the IRSS, professor of parasitology and principal investigator of the trial, confided to SciDev.Net that “this is yet another first in the history of malaria vaccine research. »
“This means that we can maintain an efficacy of more than 75% over the long term if we administer a booster dose and this should allow children living in malaria-endemic regions such as Burkina to be very well protected once morest malaria at the age when they are most vulnerable,” he adds.
The vaccine – which Halidou Tinto describes as an improved version of the RTS,S vaccine being rolled out in a number of African countries – had already shown 77% efficacy in the first year in an earlier trial in 2021.
The phase two trial was extended for two years to see if additional booster doses are needed to maintain this high efficacy over time.
The Burkinabé researcher says he is “optimistic” that the latest results can also be replicated in an ongoing phase three trial involving 4,800 children in Burkina Faso, Mali, Kenya and Tanzania. Results are expected later this year.
Deployment in 2023
The R21 vaccine, developed at the Jenner Institute at the University of Oxford, is licensed for production by the Serum Institute of India (GIVE).
“We are already planning, in collaboration with our partners (…) to undertake from 2023 a programmatic deployment of R21 on a population of at least 250,000 children in Burkina Faso in order to accelerate the agenda of deployment of this vaccine on a large scale in Africa,” says Halidou Tinto.
He adds that SII had committed to producing at least 100 to 200 million doses of the R21 vaccine per year subject to the WHO issuing a recommendation for its deployment.
“This will supplement the only vaccine currently recommended by the WHO (RTS,S) whose current production capacity cannot meet global demand,” says the researcher.RTS,S, the world’s first malaria vaccine, was recommended by WHO in October 2021 for use in at-risk children in sub-Saharan Africa and other areas with moderate to high transmission of malaria caused by the Plasmodium parasite falciparum.
However, scientists have stressed the need for further vaccine development and investment in research.
The director of the Jenner Institute, Adrian Hill, co-author of the study on R21 published in the Lancet Infectious Diseases says it’s “the best data yet” for any malaria vaccine.
“We are delighted to see that a standard four-dose vaccination regimen can now, for the first time, achieve the high level of efficacy over two years that has been an ambitious goal for malaria vaccines for so many years” , he points out.
Adrian Hill also says that this vaccine would provide “long-lasting protection” to the most important group that needs it: young African children. But he points out that the 77% accuracy of the vaccine depended on other control measures such as insecticides and mosquito nets, which should continue to be used.
“Scientifically speaking, it can be said that RTS,S suffered from a saturation of the immune response induced by an excess of surface antigens of the hepatitis B virus. It is on the basis of this observation that Professor Adrian’s team Hill proceeded with a simplification of the constitution of RTS,S by reducing the quantity of the HBs antigen, thus allowing a better immune response once morest the parasite”, compares Halidou Tinto.
According to his explanations, another “major” change is the use, for R21, of an adjuvant other than that which had been used in the development of RTS,S
Effectiveness in real conditions
James Tibenderana, who will take over the general management of the non-profit organization Malaria Consortium in October 2022, called the results of these trials “remarkable”.
Tibenderana, who was not involved in the R21 trials, said the rapid development and deployment of vaccines once morest COVID-19 showed that it was possible to shorten the time to develop and distribute vaccines while mitigating risks.
“I hope these findings will motivate increased and sustained investment in research and development of malaria vaccines, and their equitable access, as they prevent malaria infections and save lives,” he says.
On a completely different level, Halidou Tinto recalls that malaria is most prevalent in Africa more than anywhere else and that therefore it is good form that solutions to this disease be sought on African soil.
“On a purely scientific level, carrying out vaccine trials in Africa assures us that the efficacy of a candidate vaccine at the end of the trial will reflect its performance in the real conditions of its use and that it will not be different due to variability in the epidemiological facies or the genetic diversity of malaria parasites,” says the researcher.
He concludes by saying that conducting these trials in Africa also contributes to building the capacity of research institutions on the continent through training as well as that of pharmaceutical regulatory authorities who “will be more efficient”.
