Shares of Novavax closed nearly 50% higher on Monday as Wall Street cheered the company’s new multibillion-dollar deal with French drugmaker Sanofi that sparked a dramatic turnaround for the struggling vaccine maker.

Novavax’s stock almost doubled on Friday after it announced the licensing agreement with Sanofi. Novavax on Friday said the deal allows the company to remove its “going concern” warning, which it first issued in February 2023 due to major doubts about its ability to stay afloat.

“It really does help our business. It keeps us well capitalized, it takes the going concern off, it gives us the chance to pivot our strategy more toward what we’re best at — to bring additional value to all of our stakeholders, including our shareholders,” Novavax CEO John Jacobs told CNBC in an interview. 

Under the agreement, Sanofi will take a less than 5% stake in Novavax. The deal also entitles Novavax to an upfront cash payment of $500 million and future payments contingent on certain milestones, as well as royalties. 

Sanofi, one of the world’s largest vaccine makers, will co-market Novavax’s Covid vaccine in most countries starting in 2025. The deal also allows Sanofi to use Novavax’s Covid shot and flagship vaccine technology, Matrix-M adjuvant, to develop new vaccine products. The shots include combination jabs targeting Covid and the flu. 

In a note Sunday, Jefferies analyst Roger Song said the deal will provide significant capital to Novavax and support the company’s growth. 

“Economically, the deal is highly lucrative and impactful,” Song wrote. 

He said the upfront payment helps remove investor worry about Novavax’s going concern warning, and that milestone payments are “significant and relatively near-term” for the company since they are not tied to sales. Meanwhile, royalties will provide a steady revenue stream each year, Song said. 

He added that the deal “validates” the company’s protein-based vaccine platform. 

Novavax’s shot is the first Covid vaccine to use protein technology, a decades-old method for fighting viruses used in routine shots against Hepatitis B and shingles. Health officials view the vaccine as a valuable alternative for people who do not want to take messenger RNA jabs from Pfizer and Moderna.

In a note on Sunday, Leerink Partners analyst David Risinger said he is interested to see how effective Sanofi is at raising consumer awareness about how the side effects of Novavax’s Covid vaccine are easier for patients to tolerate compared to competing shots from Pfizer and Moderna.

Risinger noted that consumer hesitancy around Covid boosters has come in part from fears about the fatigue and discomfort associated with Pfizer’s and Moderna’s shots. 

The firm expects Sanofi “to drive greater commercial success of [Novavax’s] vaccine starting in 2025, due to its commercial scale and contracting abilities, but it is difficult to predict the magnitude of impact,” Risinger wrote. 

He added that there could be “further upside” for Sanofi and Novavax if they develop a combination Covid and flu vaccine that has advantages over the mRNA combo shots being developed by Pfizer and Moderna.