 Imagine if we could develop vaccines that protect against deadly diseases in months rather than years. Developing and testing a new vaccine is usually a slow process that can take more than 10 years and cost hundreds of millions of dollars. But scientists can now speed up this process and save money using human infection studies, which can much more quickly show how effective vaccines are at protecting against disease. Researchers in Kenya plan to use human infection studies to accelerate the testing of a new vaccine that may protect against infection with Shigella bacteria, which causes stomach pain, vomiting and diarrhea, and affects more than 120 million people globally each year. For young children whose immune systems are not so robust, it can be quite severe and can cause death. So when you think about the scale of the problem, then really it's the fourth leading cause of death in children under five across the world. New vaccines are being developed to prevent the illness. Scientists at the Kenry Wellcome Trust Research Programme in Kenya have already shown that one is safe to use in people. They now plan to test its effectiveness using a human infection study to more quickly establish how well it works and understand the immunity to the infection it might provide. A vaccine dose is given to volunteers, but rather than wait for them to acquire the disease in the outside world, researchers also infect the volunteers with a precise dose of Shigella bacteria in a controlled and safe environment. We're going to set that up here in Kilefi within the next year and a half. If volunteers become ill, help is close to hand and doctors give them medical treatment known to work against the disease. If they don't become sick, it means the researchers quickly know that the vaccine prevents the illness. Such human infection studies allow scientists to more precisely discover how people develop immunity to diseases and for how long. That helps accelerate the development of new vaccines, saving costs and lives. As a big step ahead, we can use it as a way of prioritising which vaccines work best. Innovations like this will help us save more lives. Let's get behind the future of vaccines.