SEOUL/SINGAPORE : China is forging ahead in the race to develop a vaccine to help control the COVID-19 pandemic, with Sinovac Biotech's experimental vaccine set to become the country's second and the world's third to enter final stage testing later this month.While a laggard in the global vaccine industry, China, where the new coronavirus is thought to have originated, has brought state, military and private sectors together in a quest to combat a disease that has killed over 500,000 people worldwide.Many other countries, including the United States, are coordinating closely with the private sector to try to win the vaccine development race, and China faces many challenges.Its success in driving down COVID-19 infections makes it harder to.