Philippine President Rodrigo Duterte vowed on Monday to prioritise buying a Covid-19 vaccine to be made available by Russia or China, taking a swipe at western pharmaceutical firms asking for advance payment for their offers. South Korea meanwhile said it will secure early supply of vaccines from international manufacturers for 30 million people.Duterte expressed optimism that the Southeast Asian country, which has recorded the region’s highest number of coronavirus cases at nearly 266,000,…