Virus Outbreak Vaccine Race

In this screen grab from video issued by Britain's Oxford University, a volunteer is injected with either an experimental COVID-19 vaccine or a comparison shot as part of the first human trials in the U.K. to test a potential vaccine, led by Oxford University in England on April 25, 2020. About 100 research groups around the world are pursuing vaccines against the coronavirus, with nearly a dozen in early stages of human trials or poised to start. (University of Oxford via AP)