2nd LD: WHO validates China's Sinovac COVID-19 vaccine for emergency use Xinhua 02 Jun 2021, 02:30 GMT+10 GENEVA, June 1 (Xinhua) -- The World Health Organization (WHO) validated on Tuesday the CoronaVac COVID-19 vaccine developed by Chinese pharmaceutical company Sinovac Biotech for emergency use. WHO recommends the vaccine for use in people 18 years and older, in a two-dose schedule with a spacing of two to four weeks, according to a statement. The efficacy results showed that the Sinovac vaccine prevented symptomatic disease in 51 percent of those vaccinated, and prevented severe COVID-19 and hospitalization in 100 percent of the studied population, according to the WHO's Strategic Advisory Group of Experts on Immunization (SAGE).