Osaka-based drugmaker Shionogi & Co. said its experimental COVID-19 vaccine was found safe and effective in a study, potentially creating an indigenous supply source for the nation as it races to complete a booster drive in hopes of curbing future outbreaks.

The recombinant protein-based vaccine that was being tested as a booster shot met its primary endpoint in the Phase 2/3 trials, Shionogi said in a statement Friday announcing the interim report’s findings. There were no serious treatment-related adverse events, deaths or adverse events of special interest, it said.

The data support regulatory approval of the vaccine that could bolster the government’s efforts to tackle the virus that has already infected more than 5 million people in the country and killed more than 24,000. The world’s third-largest economy currently relies on shots from Pfizer Inc. and Moderna Inc. for the bulk of its supplies.