BioNTech SE eased concerns Friday over the mass production of COVID-19 vaccines as the company said it’s on track to produce 50 million doses with partner company Pfizer Inc., Bloomberg reported.

According to a statement shared with the media outlet, BioNTech SE looks to raise its production capacity beyond 1.3 billion doses.

The vaccines made by U.S.-based Pfizer and its German partner BioNTech were tested on tens of thousands of people. And while that study isn’t complete, early results suggest that the vaccine is 95% effective at preventing mild to severe COVID-19 infections. The companies told regulators that of the first 170 infections detected in study volunteers, only eight were among people who had received the actual vaccine and the rest had gotten a dummy shot.

The companies also reported no serious side effects, although vaccine recipients may experience temporary pain and flu-like reactions immediately after injections.

But experts caution that a vaccine cleared for emergency use is still experimental and the final testing must be completed. Still to be determined is whether the Pfizer-BioNTech shots protect against people spreading the coronavirus without showing symptoms. Another question is how long the protection lasts.