2022 saw several major developments in the fight against malaria.
- GlaxoSmithKline announced that its new malaria vaccine, R21, reduced infections by around 80% in a small trial.
- A monoclonal antibody therapy showed promise.
- Genetically modifying mosquitoes to make their offspring infertile — a long-heralded method of getting rid of the mosquitoes that spread malaria — was shown to actually work.
- New techniques were developed to grow malaria parasite sporozoites in vitro, making it easier to scale up an immunity-boosting program.
Malaria is an ongoing humanitarian disaster. Every year, about half a million people die of the disease, and about 80% of victims are children. We have some effective drugs, and ways of preventing infection such as bed nets, and those methods led to a roughly 50% drop in malaria deaths between 2000 and 2015. But since then, progress has plateaued.
It’s easy to get overexcited by early-stage health science developments — a cancer drug that won’t reach the market for 15 years or a dementia treatment that shows promising results, in mice. But progress on malaria in 2022 looks real. The obstacles now feel less technical and scientific, and more to do with political will.
GSK’s R21 vaccine is only the second successful malaria vaccine ever developed. The first, RTS,S, which was approved by the World Health Organization last year, was only about 50% effective.
But studies suggested that even that less effective vaccine — if 30 million doses of it could be administered in sub-Saharan Africa annually — would save the lives of about 22,000 children under five every year.
Rollout has been slow so far, but Nature reports that the Serum Institute of India has committed to producing 200 million doses of R21 annually, should it be approved.
The Antibody Therapy
In November, a monoclonal antibody therapy also showed promise. Antibodies are the proteins our bodies make to fight off disease. Monoclonal antibody therapies are essentially lab-grown versions of them, targeted to a specific pathogen, given to prevent illness.
Early trials suggested that a new drug was between 75% and 90% effective at stopping infection, depending on the dose.
The Sporozoite Shift
A more technical, but still important, breakthrough was the development of techniques to grow malaria parasite sporozoites in vitro.
Sporozoites are the stage of the parasite lifecycle that gets injected into humans: They grow in mosquitoes’ salivary glands. Injecting people with dead sporozoites highly effectively inoculates them against malaria, but until now they have needed to be harvested by hand from mosquitoes, which is impractical to do at scale.
Scientists announced in December that they had successfully bred them in the lab. As well as directly allowing the sporozoites to be used as vaccines, it should also speed research into the malaria lifecycle and therefore other therapies.
The Genetic Modification
For years, scientists have been interested in genetically modifying male mosquitoes so that any female offspring they have are infertile, hopefully causing the population to crash. Also, only the females bite and spread disease.
A trial using that technique found that mosquito populations fell by 96% within a year in the areas they released the males. It was carried out in an area with high prevalence of dengue fever, but would be similarly effective against malaria.