https://apnews.com/7cceba422eb5c430dc56673c84c01ac9 > LONDON (AP) — U.K. researchers are preparing to begin a controversial experiment that will infect healthy volunteers with coronavirus to study the disease in hopes of speeding up the development of a vaccine. > The approach, called a challenge study, is risky but proponents say it may produce results faster than standard research, which waits to see if volunteers who have been given an experimental treatment get sick. The government is preparing to invest 33.6 million pounds ($43.4 million) in the study.