Scientists are working to develop a vaccine capable of stopping the spread of a mysterious new coronavirus that has infected thousand of people, mostly in China. Government scientists in China, the United States and Australia, as well as those working at Johnson & Johnson, Moderna Therapeutics and Inovio Pharmaceuticals are all working quickly to develop a vaccine. The hunt began Jan. 10, when Chinese scientists posted the genetic makeup of the virus on a public database. The next morning, researchers at the National Institutes of Health’s Vaccine Research Center in Maryland went to work. Within hours, they had pinpointed the parts of the genetic code that could be used to make a vaccine. Historically, vaccines have been one of the greatest public health tools to prevent disease. But even as technology, genomics and global coordination have all improved, allowing researchers to move at top speed, vaccine development remains an expensive and risky process.