On October 6, the World Health Organization endorsed a malaria vaccine for the first time ever. After years of testing, the vaccine was shown to be safe and effective at preventing the deaths of thousands of children in Sub-Saharan Africa. The WHO's backing of this Malaria vaccine is both a breakthrough in scientific research and an important moment in human history. Margaret McDonnell, executive director of Nothing But Nets at the UN Foundation, explains why this new malaria vaccine is so promising