A new study finds the novel coronavirus that emerged in China mutated in Europe in February to become more contagious, speeding its spread around the globe. The report from the Los Alamos National Laboratory also warns the mutated strain could leave people vulnerable to a second infection of COVID-19. The finding has not been peer-reviewed, and the director the National Institutes of Health urged caution, saying the study draws sweeping conclusions about the virus that might not hold up to further scrutiny. The authors of the study said they released their findings early so that people working on vaccines could see their results.