Study design and participants
DISEASE
This single-site, randomized, controlled, open-label phase IV clinical trial was conducted by the Shandong Provincial Center for Disease Control and Prevention (CDC) in Rushan, Shandong province, China (NCT04953325). Participants 18 years or older were recruited and randomized to evaluate the immunogenicity and safety of an inactivated COVID-19 vaccine (CoronaVac). The trial was approved by the Shandong Provincial CDC Ethics Committee and was conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice. All participants provided their written informed consent prior to screening.