The Vaccine Safety Datalink (VSD) is a collaborative project between CDC’s Immunization Safety Office, integrated health care organizations, and networks across the U.S. The VSD started in 1990 and continues today in order to monitor safety of vaccines and conduct studies about rare and serious adverse events following immunization. As of September 28, 2022, there are 13 VSD sites that provide clinical, methodological, and data expertise; 11 are data providing sites.
The VSD uses electronic health data from participating sites to monitor and assess the safety of vaccines. This includes information on vaccines: the kind of vaccine given to each patient, date of vaccination, and other vaccinations given on the same day. The VSD also uses information on medical illnesses that have been diagnosed at doctors’ offices, urgent care visits, emergency department visits, and hospital stays. The VSD conducts vaccine safety studies based on questions or concerns raised from the medical literature and reports to the Vaccine Adverse Event Reporting System (VAERS). When there are new vaccines that have been recommended for use in the United States or if there are changes in how a vaccine is recommended, the VSD will monitor the safety of these vaccines.
The VSD has a long history of monitoring and evaluating the safety of vaccines. Since 1990, investigators from the VSD have published many studies to address vaccine safety concerns. Examples of VSD’s work include the following: