Production of another potential vaccine against COVID-19 will begin within weeks, its developers Sanofi and GlaxoSmithKline said Thursday as they launched a large trial enrolling 35,000 adult volunteers in the United States, Asia, Africa and Latin America. The study will test vaccine candidate formulas against the original coronavirus that spread from Wuhan, China, and against the variant first seen in South Africa, the pharmaceutical firms said. If the trial is successful, regulators could approve the vaccine for use in the last three months of the year, the drugmakers said in a statement.