Global COVID Vaccine Safety (GCoVS)

The simultaneous development of so many vaccines for COVID-19 and their anticipated deployment in both high- and low-middle- income countries to meet the global need is unprecedented. If a true rare safety issue with one of these COVID-19 vaccine candidates exists, it is likely to only be detected post-introduction, when millions of people (including at risk subpopulations) will have been vaccinated. 

To address the need for very large, coordinated safety assessments of COVID-19 vaccines in different populations around the world, the U.S. Centers for Disease Control and Prevention (CDC) funded* the Global Vaccine Data Network™ (GVDN®) for three-years to conduct a programme of activities. The Global COVID Vaccine Safety (GCoVS) project uses the GVDN and its Global Coordinating Centre to manage and work with the global data partners that have experience in the analyses of vaccine safety surveillance using electronic databases and vaccine safety evaluation to evaluate and compare COVID-19 vaccine safety. In August 2022, the U.S. Centers for Disease Control and Prevention granted additional funding to extend the GCoVS project by two years and expand the number of sites participating globally.

Our overall approach includes several activities, most occurring simultaneously:

  • Develop background rates for adverse events of special interest for each partner site and display these on a publicly available dashboard
  • Develop common data dictionary for all studies
  • Conduct observed over expected assessments for selected adverse events of special interest
  • Conduct association studies for events that have been identified as likely associated with COVID-19 vaccines
    • Myocarditis and pericarditis and mRNA vaccines
    • Thrombosis with thrombocytopenia syndrome/vaccine-induced immune thrombotic thrombocytopenia (TTS/VITT) and viral vector vaccines
    • Guillain-Barré syndrome (GBS) and viral vector vaccines
  • Assess risk of vaccine mediated enhanced disease
  • Assess safety in pregnancy
  • Conduct genomic assessments for cases and controls for myocarditis, TTS/VITT, and GBS
  • Develop communications to support vaccine confidence

The first outputs are expected from mid-2022.


*This project is supported by the Centers for Disease Control and Prevention (CDC) of the U.S. Department of Health and Human Services (HHS) as part of a financial assistance award totalling US$10,108,491 with 100% funded by CDC/HHS. The contents are those of the author and do not necessarily represent the official views of, nor an endorsement, by CDC/HHS, or the U.S. Government. For more information, please visit