What has been the status quo of case definitions for immunization safety purposes?
Medical dictionaries for regulatory affairs32–34—as well as case definitions for adverse drug reactions35—have been developed and implemented previously. However, relatively little work to develop case definitions for use in immunization safety has occurred to date.10, 36, 37Those developed are not widely implemented, nor do they represent an exhaustive set of definitions or provide guidelines for the standardized collection, analysis, and presentation of data that are needed for data comparability. This leads to the current situation in which, for example, the respective Brighton working groups for fever and local reactions found 9 different cut-off temperatures for fever in 120 vaccine safety studies, and 11 different cut-off diameters for local reaction size in 102 vaccine studies. Ideally, newly developed case definitions would be evaluated for their applicability, reliability, sensitivity, and specificity in their settings of future use. However, this has largely not been done; ca
