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“Childhood Vaccine Studies: The Act called for the Institute of Medicine [IOM] to review existing studies and medical literature and provide a foundation for recommendations on vaccine injury causation. In reports issued in 1991 and 1994, IOM published several conclusions regarding the scarcity of knowledge about vaccine safety, citing severe limits in data and research capability. Of the 76 adverse events IOM reviewed for a causal relationship, 50 (66 percent) had no or inadequate research.
Specifically, IOM Committees identified the following limitations of existing knowledge: 1) Inadequate understanding of biologic mechanisms underlying adverse events; 2) Insufficient or inconsistent information from case reports and case series; 3) Inadequate size or length of follow-up of many population-based epidemiological studies; 4) Limitations of existing surveillance systems to provide persuasive evidence of causation, and 5) Few published epidemiological studies.
IOM warned that ‘if research capacity and accomplishments [are] not improved, future reviews of vaccine safety [will be] similarly handicapped.’ IOM recommends: ‘More research could be done on potential long-term adverse effects from vaccines as well as the potential of vaccines to induce or worsen immune disorders.’ CDC agrees that there remains ‘uncertainty about estimates of the risk associated with vaccination’ and that to ‘continue research to improve the understanding of vaccine risks is critical.’…
Vaccine Adverse Events Reporting System: … While the Vaccine Adverse Events
Reporting System [VAERS] may be lauded as the ‘‘front line’’ of vaccine safety, the lack of enforcement provisions and effective monitoring of reporting practices preclude accurate assessments of the extent to which adverse events are actually reported. Former FDA Commissioner David A. Kessler has estimated that VAERS reports currently represent only a fraction of the serious adverse events.
The quality of VAERS data has been questioned. Because reports are submitted from a variety of sources, some inexperienced in completing data forms for medical studies, many reports omit important data and contain obvious errors. Assessment is further complicated by the administration of multiple vaccines at the same time, following currently recommended vaccine schedules, because there may be no conclusive way to determine which vaccine or combination of vaccines caused the specific adverse event.”