France's Sanofi and Britain's GlaxoSmithKline has launched a late-stage human trial for their recombinant Covid-19 vaccine candidate that they hope to get approved by the end of this year, Reuters reports.

The two companies, which earlier this month reported positive interim results, confirmed their double-blind, placebo-controlled, phase III study would include more than 35,000 adults in the United States, Asia, Africa, and Latin America.

“In a two-stage approach, the study will initially investigate the efficacy of a vaccine formulation targeting the original virus, while a second stage will evaluate a second formulation targeting the B.1.351 virus,” Sanofi said.

The virus lineage known as B.1.351 was first detected in South Africa.