Shares of Novavax (NVAX) tumbled 5.85% in pre-market trading on Thursday, following news that the U.S. Food and Drug Administration (FDA) has missed a crucial deadline regarding the company's COVID-19 vaccine. This development has sparked concerns among investors about potential delays in the vaccine's approval process.

According to reports, the FDA failed to make a key decision regarding Novavax's COVID-19 vaccine within the expected timeframe. This missed deadline comes just days after the FDA's vaccine chief was unexpectedly removed from their position, adding another layer of uncertainty to the situation.

The delay in the FDA's decision-making process could have significant implications for Novavax, a company that has been working diligently to bring its COVID-19 vaccine to market. Investors appear to be reacting negatively to this news, as reflected in the sharp pre-market decline of the company's stock price. The situation underscores the challenges and uncertainties faced by pharmaceutical companies in the highly regulated and time-sensitive field of vaccine development and approval.