Moderna, Inc.'s stock soared 5.06% during intraday trading on Thursday, following a significant positive development regarding its regulatory pipeline.

The surge comes after the U.S. Food and Drug Administration reversed its previous decision and agreed to review an amended application for Moderna's mRNA-1010 seasonal influenza vaccine. This follows a "refusal-to-file" letter issued by the agency just last week, which had initially rejected the submission and raised concerns among investors.

Analysts have responded positively to the swift regulatory U-turn. William Blair raised its probability of regulatory success for the flu vaccine to 55% from a previous estimate of 10%. The development improves the prospects for Moderna's vaccine candidate, which is seeking approval for adults aged 50 and older, potentially making it available for the 2026-2027 flu season.