IMAGE: Testing for malaria at a clinic in Myanmar
The fight against malaria has taken a significant step forward with the approval by the European Medicines Agency of the vaccine Mosquirix (also known as RTS,S).
The first licensed malaria vaccine that’s intended for human use, Mosquirix is awaiting approval by the World Health Organization which would clear the way for its application across the regions.
But elimination of malaria will require a range of vaccine approaches to protect against infection, against the disease and to reduce transmission, according to Burnet Institute researchers, Professor James Beeson and Dr Freya Fowkes.
In their joint contribution to a Forum on malaria eradication and elimination published in BMC Medicine, Professor Beeson and Dr Fowkes outline the different vaccine candidates against the malaria parasites Plasmodium falciparum and P. vivax.
They argue that for elimination to be achieved and sustained, vaccines combining multiple targets and stages of infection will need to be implemented in co-ordination with other malaria control interventions.
“The increasing emphasis on achieving elimination of malaria from numerous regions, and ultimately global eradication, highlights the need for strongly efficacious vaccines that protect against clinical disease and infection, and also prevent ongoing transmission in populations,” Professor Beeson and Dr Fowkes said.
“To achieve this will almost certainly require multi-component vaccines that include multiple antigens from different life stages.
“The challenges in achieving highly efficacious vaccines with single antigen approaches also suggest that multi-antigen and multi-stage vaccines will be required."
Mosquirix, which targets the early stage of infection when the parasite enters or matures in an infected cell, was shown to be effective in 30-66 percent of infants and young children in Phase II trials in Africa.
In later trials there was evidence of waning efficacy, though efficacy was improved in children who received a booster.
Professor Beeson and Dr Fowkes said it was important for vaccines to demonstrate sustained efficacy over several years.
“While the efficacy of RTS,S is modest and the future effectiveness of RTS,S is yet to be established, the number of clinical cases averted by its implementation is likely to be considerable given the global burden of malaria,” the researchers said.
“RTS,S may prove to be a valuable addition to malaria control efforts. However, the future development of more efficacious and long-lasting vaccines is likely to be needed to achieve elimination from many countries and regions.”
It’s estimated that 3.3 billion people globally are currently at risk of malaria infection.
Malaria causes around 600,000 deaths per year, and while mortality rates continue to fall, the disease remains a major global health threat.