In 2013, almost 600,000 people died of malaria, a disease caused by a parasite passed to humans through mosquito bites. But these deaths–mostly among children in Africa–are preventable. For years researchers have been working on different tactics to reduce malaria’s prevalence, such as creating innovative drugs or highly effective repellants as well as engineering the mosquitoes themselves to prevent the disease from spreading. After four years of tests on thousands of infants and children, an anti-malarial vaccine has emerged as one of the most promising candidates to prevent the spread of the disease. The results of the clinical trial are published this week in The Lancet.

To test the vaccines, researchers enrolled about 15,000 children between six weeks and 17 months old, some of whom were infected with malaria, across seven countries in sub-Saharan Africa. Each child was given a dose of the vaccine every month for three months, and one group was given a booster vaccine 18 months later. After the first year, the trial groups had 50 percent fewer cases of malaria than the projected number. When researchers checked back in with the kids three years after their initial vaccine, 36 percent of the children in the booster shot group didn’t have malaria-related hospital visits in comparison to the non-booster group.

Though the vaccine isn’t fully effective, it’s promising enough to make public health officials and researchers alike feel hopeful. “While the levels of protection the vaccine offers against clinical malaria may seem relatively low, they are better than any other potential vaccine we currently have,” Mike Turner, an infection specialist at Wellcome Trust, told the BBC. “The findings are not only important in their own right but also in signposting a road to developing better vaccines in the future.”

In the near future, the European Medicines Agency (essentially the European version of the Food and Drug Administration) will evaluate the vaccine; if it decides favorably, the World Health Organization could start recommending the vaccine for use around the world as early as October.