Novavax, which makes the Nuvaxovid vaccine used to treat Covid-19, posted huge sales gains for the past three years during the height of the pandemic. But the company is now facing serious financial challenges — and has even warned it may not be able to survive. The Gaithersburg, Maryland-based company said its forecast “is subject to significant uncertainty,” particularly with regard to future sales and funding from the US government, the company said in its latest earnings report after the closing bell Tuesday. “Given these uncertainties, substantial doubt exists regarding our ability to continue as a going concern,” the company added. Shares of Novavax\n \n (NVAX) plunged more than 25% in early morning trading to a new multi-year low of under $7. The stock is now trading below where it was just before the start of the pandemic in early 2020. Novavax hit a 52-week high of about $91 last year and was trading above $330 in February 2021. Novavax still has about $1.3 billion in cash on its balance sheet. But that’s down from more than $1.5 billion at the end of 2021. The company continues to hemorrhage money, losing $182 million in the fourth quarter alone and $658 million for all of last year. That’s on top of a net loss of $1.7 billion in 2021. Despite this, Novavax’s new CEO expressed optimism about the company’s prospects. “Much has been achieved over the past three years, and based on the foundation that has been laid to date, I believe that Novavax has significant potential for a bright future,” said Novavax CEO John Jacobs, a veteran biotech executive who joined the company in January. Still, Jacobs conceded that Novavax faces numerous daunting challenges. He said the company needs to “deliver a competitive product for the upcoming 2023 fall vaccination season,” reduce its rate of spending and manage its cash flow better and find ways to boost sales beyond its Nuvaxovid vaccine alone. “We believe that if we succeed in executing against these priorities, we will position the company well for long-term success,” Jacobs said. Novavax isn’t the only Covid-vaccine maker to disappoint Wall Street, though. Investors are starting to worry that the big lift from vaccine sales for other top pharma and biotech companies may be fleeting: Shares of Pfizer\n \n (PFE) and its vaccine partner BioNTech\n \n (BNTX), as well as rival Moderna\n \n (MRNA), have all plummeted in the past year.