A malaria vaccine developed by Oxford University was found to have "high-level efficacy" in phase II trials, according to a pre-print study released on Friday.

Why it matters: Malaria kills over 400,000 people a year, more than half of them children under the age of 5. Deaths have fallen in half over the past 20 years thanks to investment in prevention and drugs, but a truly effective malaria vaccine would represent one of the greatest victories in the history of public health.

Details: The vaccine was found to be 77% effective, becoming the first to surpass the World Health Organization's goal of having a vaccine with at least 75% efficacy by 2030, Oxford University said in a statement.

• "[N]o serious adverse events related to the vaccine" were noted, according to Oxford.
• The trial included 450 participants between the ages of 5 months and 17 months, and lasted over 12 months.
• The participants were split into three groups: Those who received a higher dose were found to be 77% less likely to develop malaria, while those with a lower dose recorded 71% efficacy. The rest of the participants received a rabies vaccine as the control group.

What's next: "Larger trials in nearly 5,000 children between the ages of five months and three years will now be carried out across four African countries, to confirm the findings," BBC writes.

Worth noting: This study is not yet peer-reviewed. Oxford's Jenner Institute is the same that successfully developed the AstraZeneca coronavirus vaccine.