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Vaccine Safety Datalink (VSD)

The Vaccine Safety Datalink (VSD) is a collaborative effort between CDC's Immunization Safety Office and 9 managed care organizations (MCOs). The VSD was established in 1990 to monitor immunization safety and address the gaps in scientific knowledge about rare and serious events following immunization.

The VSD includes a large linked database that uses administrative data sources at each MCO. Each participating site gathers data on vaccination (vaccine type, date of vaccination, concurrent vaccinations), medical outcomes (outpatient visits, inpatient visits, urgent care visits), birth data, and census data.

The VSD allows for planned immunization safety studies, as well as timely investigations of hypotheses that arise from review of medical literature, reports to the Vaccine Adverse Event Reporting System (VAERS), changes in immunization schedules, or the introduction of new vaccines.

The VSD has proven to be a highly effective tool for evaluating immunization safety. Since 1990, investigators from the VSD has published numerous scientific studies on the best ways to use existing immunization safety data. The VSD has addressed the following concerns:

  • A study that compares the risk of febrile seizures in children who receive MMRV vaccine versus children who receive MMR and varicella vaccine separately.
  • An evaluation of the VSD data to examine the safety of thimerosal-containing vaccines.
  • An evaluation of the risk of intussusception following rotavirus vaccine.
  • Conducted active surveillance of 2009 H1N1 influenza vaccine.

Managed Care Organization Sites

The Vaccine Safety Datalink and Managed Care Organizations map of the United States
  • Group Health Cooperative of Puget Sound, Seattle, Washington
  • Harvard Pilgrim Health Care, Boston, Massachusetts
  • HealthPartners Research Foundation, Minneapolis, Minnesota
  • Kaiser Permanente Northwest, Portland, Oregon
  • Kaiser Permanente Medical Care Program of Northern California, Oakland, California
  • Kaiser Permanente Colorado, Denver, Colorado
  • Kaiser Permanente of Georgia, Atlanta, GA
  • Marshfield Clinic Research Foundation, Marshfield, Wisconsin
  • Southern California Kaiser Permanente Health Care Program, Los Angeles, California

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  • To conduct population-based research on immunization safety questions
  • To evaluate immunization safety hypotheses that arise from medical literature, passive surveillance systems, adjustments to immunization schedules, and introduction of new vaccines
  • To guide national immunization policy decisions
  • To partner with healthcare providers, public health officials, and others to ensure the public has the best available information regarding the risks and benefits of immunization

Rapid Cycle Analysis

Rapid Cycle Analysis (RCA)is an active surveillance system designed to detect adverse events (possible side effects) following vaccination in near real time so the public can be informed quickly of possible risks.

VSD Data Sharing Program

Researchers can access VSD data through the VSD Data Sharing Program and the National Center for Health Statistics

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