The Global Vaccine Data Network constitutes a network of sites ready to conduct globally coordinated active surveillance epidemiologic studies of the safety of vaccines, including COVID-19 vaccines, as they are introduced. For COVID-19 vaccines, this work will be undertaken under a common protocol and will include development of background rates of adverse events of special interest (AESI) in study sites prior to the COVID pandemic and also in the first six months of 2020. The common protocol will identify these AESI with predefined time periods and age strata, and will take account of the impact of the pandemic on healthcare utilization patterns. In addition, the protocol will use common definitions and procedures for comparative analyses across sites to assess the safety of COVID vaccines as they are introduced and will include evaluation of AESI as well as procedures for identifying unanticipated events.