After losing more than 90% of its value from a peak back in 2021, Novavax ( NVAX 2.31% ) stock has finally taken off. The biotech soared 190% in two trading sessions after announcing a $1.2 billion vaccine-licensing deal with French pharmaceutical giant Sanofi. The agreement removed one huge worry that's been weighing on the stock: Novavax's ability to continue operations. The vaccine maker issued a going concern early last year, warning that if uncertainties deepened, the company would be forced to shut its doors.