What happened

Shares of Novavax (NVAX 2.95%) were skyrocketing 31.6% this week as of 3:18 p.m. ET on Thursday, according to data provided by S&P Global Market Intelligence. The big jump came after several positive developments for the vaccine maker.

On Monday, Swiss regulators recommended the use of Novavax's Nuvaxovid COVID-19 vaccine as a booster in adults ages 18 and older. Novavax's partner, SK Bioscience, also filed for South Korean approval of Nuvaxovid as a booster.

On Wednesday, Novavax announced promising data for its prototype vaccine targeting the coronavirus omicron variant. The company followed up on Thursday with encouraging data for its combination COVID-19/flu vaccine candidate.

So what

This flurry of good news was much needed for Novavax. The vaccine stock had plunged 89% coming into this week.

The decision by Switzerland's Federal Office of Public Health to recommend Nuvaxovid as a booster in adults should have the most immediate impact of this week's developments. However, the vaccine had already been given temporary authorization as a booster from Swiss regulators in September. 

Arguably the most important news for the near term, though, is the omicron booster data. Novavax announced that its omicron booster prototype produced a robust immune response. The company is playing catch-up on this front: Rivals Pfizer and Moderna have already launched omicron boosters in the U.S. 

But the biggest development for Novavax over the long term just might be its combination COVID-flu vaccine candidate's progress. The company reported positive results from a phase 1/2 study that showed the combo vaccine generated immune responses for both the novel coronavirus and influenza strains.

Now what

Novavax plans to advance its combination COVID-flu vaccine candidate into phase 2 testing later this year. The big question for the company for now is how quickly it will be able to file for and secure authorizations for its omicron booster.