Shares of Novavax Inc. tumbled 15% in premarket trading on Wednesday following a day in which growing concern about the new coronavirus sent shares of vaccine developers soaring. On Tuesday after the market closed, Novavax filed an S-1 seeking to sell more than $100 million of its stock. The clinical-stage biotechnology company, which is developing a flu vaccine, told analysts it is developing clones from the new coronavirus as part of the first steps in developing a vaccine to treat the newly identified virus. “We don’t expect Novavax will run human trials without non-dilutive government funding,” Ladenburg Thalmann’s Michael Higgens wrote in a note. “The timing for such support in our view depends on how severe and uncontrolled the 2019-nCoV becomes.” Novavax in 2013 had developed a vaccine for Middle East respiratory syndrome (MERS), which is also a coronavirus. This coronavirus was first identified in Wuhan City, China, and has infected more than 300 people and killed at least six more. The Centers for Disease Control and Prevention said Tuesday that a U.S. resident who had traveled to Wuhan and is now in Washington state is currently being treated. He is the first U.S. resident to be diagnosed with the virus. Novavax’s stock has fallen 75% over the last year, while the SPDR S&P Biotech exchange-traded fund has climbed 13%.Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.