This study is a multisite,grouped test-negative case-control , phase Ⅳ clinical trial in population aged 18 years and older. The experimental vaccine will be manufactured by Sinovac Research and Development Co.,Ltd.The study is planned to be carried out in ten (10) selected hospitals and their catchment communities in five provinces of the Dominican Republic (DR): National District, La Altagracia, Puerto Plata, Santiago, and Santo Domingo from July 1, 2021 to April 30, 2022 . A total of 1400 subjects will be enrolled with 700 estimated clinic cases who are diagnosed as SARS-CoV-2 infection by real-time polymerase chain reaction (RT-PCR); and 700 estimated clinic controls who have a negative RT-PCR test.And subjects will receive two doses of vaccine for primary immunization .
