This background document on the Sinovac-CoronaVac vaccine was prepared by the Working Group on COVID-19 Vaccines of the Strategic Advisory Group of Experts (SAGE) on Immunization to inform SAGE deliberations. It contains the evidence summary which was considered by SAGE and served as the foundation for the WHO Interim recommendations referenced below. This background document was developed to inform the initial recommendation-making process. It is not updated on a regular basis