By Yasemin Saplakoglu - Staff Writer Live Science

Researchers have been working on developing an effective malaria vaccine for decades.

A malaria vaccine developed by the University of Oxford proved to be 77% effective in early clinical trials, suggesting it could be a possible breakthrough in the fight against the one of the world's deadliest infectious disease. 

Malaria is caused by the Plasmodium parasite transmitted to people through the bite of Anopheles mosquitoes. In 2019, there were 229 million cases of malaria worldwide and 409,000 deaths, according to The World Health Organization's (WHO) World malaria report. About 94% of all of these cases and deaths occurred in Africa and 67% of the deaths were among children under the age of 5.

Developing an effective vaccine for malaria has proved to be difficult, with many previous vaccines showing only a modest result; the highest performing malaria vaccine candidate developed to date had a 55.8% efficacy. 

This new Oxford vaccine, known as "R21/Matrx-M" is the first to pass the WHO's goal of achieving a vaccine with 75% efficacy against malaria by 2030. The results from this phase 2b clinical trial were published as a preprint in the journal The Lancet, and haven't yet been peer-reviewed.

The trial took place at the Research Institute in Health Sciences (IRSS) in Burkina Faso and involved 450 children between the ages of 5 and 17 months; a third of the participants were given a low dose of the experimental vaccine, a third were given a higher dose and a third served as a control group and were given the rabies vaccine. These children were vaccinated between early May of 2019 and early August of 2019, prior to the peak malaria season, according to a statement. 

In the 12 months after vaccination, the vaccine was 77% effective at preventing malaria in the higher-dose group and 71% effective in the lower dose group. They didn't report any serious adverse events.

The participants were then given a booster shot a year later.