Sanofi and GlaxoSmithKline have agreed to supply 200 million doses of their COVID-19 messenger RNA vaccine candidate to the World Health Organization-backed COVAX program.

The $18 billion COVAX program, which is administered by Gavi, the Vaccine Alliance, aims to vaccinate two-thirds of the world’s population by the end of 2021. China recently signed onto COVAX, making the U.S. and Russia the only major world powers that are not involved in the global initiative.

Sanofi and GSK began an early-stage study of their vaccine candidate in September and are anticipating preliminary results in December, when they plan to launch a phase 3 study. The companies hope to seek regulatory approval for the vaccine during the first half of 2021.