WASHINGTON (AP) — 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. It’s a crowded field, but researchers say that only increases the odds that a few might overcome the many obstacles that remain. At the same time, policymakers are devising plans to help compress the years it usually takes to develop a vaccine. Studies in China, the U.S. and Europe are looking for hints that vaccine candidates protect. Finding out for sure if any of the vaccines work in the real world comes next.