An overview of the vaccine adverse event reporting system (VAERS) as a surveillance system

We evaluated the Vaccine Adverse Event Reporting System (VAERS), the sponta neous reporting system for vaccine-associated adverse events in the United Slates, as a public health surveillance system, using evaluation guidelines from the Centers for Disease Control and Prevention. We found that VAERS i s simple for reporters to use, flexible by design and its data are availabl e in a timely fashion. The predictive value positive for one severe event i s known to be high, but for most events is unknown. The acceptability, sens itivity and representativeness of VAERS are unknown, The study of vaccine s afety is complicated by underreporting, erroneous reporting, frequent multi ple exposures and multiple outcomes. (C) 1999 Elsevier Science Ltd. All rig hts reserved.