(AP) — U.K. researchers are preparing to infect healthy young volunteers with the new coronavirus to study the disease in hopes of speeding up development of a vaccine. The approach, called a challenge study, is risky but proponents say it may produce results faster than standard research. Imperial College London said Tuesday the study will involve volunteers between 18 and 30. Peter Openshaw, co-investigator on the study, says “deliberately infecting volunteers with a known human pathogen is never undertaken lightly. However, such studies are enormously informative.” Researchers will aim to determine the smallest level of exposure needed to cause the disease, then study how potential vaccines work in the body.