US-based biotech firm Moderna is actively preparing for a potential commercial launch of mRNA-1273, its COVID-19 vaccine, the company's CEO has said.

The announcement comes amid an unprecedented race worldwide to bring a vaccine to protect people from COVID-19.

Moderna announced progress across its portfolio of pipeline assets presented at its annual R&D Day on Thursday.

"The pipeline has matured with our COVID-19 vaccine in a Phase 3 study and four candidates in Phase 2 studies," Moderna's Chief Executive Officer Stephane Bancel said in a statement.

"We are actively preparing for a potential commercial launch of mRNA-1273, our COVID-19 vaccine, and we continue to expand the breadth of Moderna's platform," he said.

Moderna revealed that the Phase-3 study of its COVID vaccine candidate, mRNA-1273, involving 30,000 volunteers in the US, has enrolled 25,296 participants as of September 16.

The company said that 10,025 participants have received their second vaccination to date.

To provide additional transparency in the context of the pandemic, the company also made Phase 3 protocol available online.

Amid calls for greater transparency by vaccine makers, Pfizer, which is also conducting the Phase-3 trial of its COVID-19 vaccine candidate, joined Moderna in making blueprints of its study available.

The revelations are aimed to address concerns that pressure to bring out a vaccine before the November US presidential election could lead to unsafe products.