16 adults drink diarrhea-producing smoothie to help scientists make vaccine

Sixteen young adults drank shot glasses worth of cloudy, salty liquid that they knew was infused with diarrhea-producing shigella bacteria at a vaccine trial at the University of Maryland. They also knew that bacteria would — in all likelihood — give them an excruciating case of dysentery. And it did.

The controlled process to test the vaccine candidate by “challenging” volunteers with a pathogen and seeing how they fared. Each one of the candidates earned at least $7,000 for participating in the trial.

Every year, hundreds of thousands of children and older adults around the world die after contracting shigella. There is no approved vaccine against the bacteria, which is the second-leading cause of diarrhea death globally.

People around the world get shigella the same way after sticking the bacteria in their mouth. Often, people are exposed by drinking contaminated water, eating food that has been prepared or handled by someone with dirty hands, or through coming into direct contact with an infected person’s poop.

Scientists at the Institut Pasteur in France have been developing a vaccine against shigella for several years. It was tested initially in Israel and is now being tried out in several dozen consenting healthy adults in Maryland as well as young kids in Kenya who may come in contact with the bacteria in their day-to-day lives.

If the current phase-two trials find the vaccine is both well-tolerated and effective at preventing severe disease, it could be tested in a large-scale real-world trial in hundreds of thousands of kids around the globe, a final regulatory move before the vaccine could be put on clinic shelves worldwide.

Dr. Wilbur Chen, who is running the trial at the University of Maryland, is hoping for 70% protection.

People with shigellosis can infect others with the bacteria. That meant the study participants had to stay inside and eat alone during the entire 11- to 12-day study.