Late-stage trial data suggest that a new COVID-flu vaccine offers good protection against both infections, but experts expect the shot's approval may be delayed.

This vaccine did previously have emergency approval by the FDA for use but can now be marketed in the U.S. for use, the letter said.

By Kamal Choudhury (Reuters) -Novavax shares jumped more than 15% on Monday after the company secured a long-awaited U.S. regulatory approval for its COVID-19 vaccine, albeit with new conditions, which helped allay some investor concerns over the future of the shot.