The companies said on Wednesday they have signed a statement of intent with vaccine alliance GAVI, which is coordinating the global plan known as COVAX, Reuters reported.
COVAX aims to deliver 2 billion vaccine doses around the world by the end of 2021, and more than 180 nations have joined the plan.
The United States and UK are leading a rush to strike deals with drugmakers to reserve supplies of experimental coronavirus vaccines.
GSK-Sanofi has currently signed a $2.1 billion deal with the US to supply it with more than 100 million doses of its coronavirus vaccine candidate. The companies also have deals with the European Union and UK.
The first results from an early mid-stage study of the Sanofi-GSK vaccine are expected in early December 2020, and the companies plan to file for regulatory approval in 2021.
The vaccine candidate uses the same recombinant protein-based technology as one of Sanofi's seasonal influenza vaccines. It will be coupled with an adjuvant, a substance that acts as a booster to the vaccine, made by GSK.