In this picture taken on April 29, 2020, an engineer shows a plastic model of the COVID-19 coronavirus at the Quality Control Laboratory at the Sinovac Biotech facilities in Beijing. - Sinovac Biotech, which is conducting one of the four clinical trials that have been authorised in China, has claimed great progress in its research and promising results among monkeys. (Photo by NICOLAS ASFOURI / AFP) / TO GO WITH Health-virus-China-vaccine,FOCUS by Patrick Baert(AFP/NICOLAS ASFOURI)