Two articles in Volume 2 address the question of detecting signals in the US Vaccine Adverse
Events Reporting System (VAERS). Co-managed by the US CDC and the US FDA, VAERS is represented as having the strengths of containing national data, being able to “rapidly detect ‘safety’ signals” and “detect rare adverse events”, and that the VAERS system brings “data to the public”. The following limitations are also listed: reporting bias, inconsistent data quality and completeness of information, lack of unvaccinated comparison group, and, importantly, that it is “not designed to assess causality” (Shimabukuro, 2021). The deep and irreconcilable incongruence between “can detect rare adverse events” and “not designed to assess causality” by Dr. Shimabukuro is noteworthy. The data in VAERS are collected passively, leading to underreporting.