Passive reporting systems have, in the past, under-reported deaths by as much as 10-fold, when compared to retrospective population-based surveys [ 44].
Therefore, robust passive reporting systems may be important to detect severe A(H7N9) cases early.
The 13 studies that we included are separated into two general categories: population-based studies and passive reporting.
Passive reporting studies should be interpreted as 'sentinel data' that provides strong inferences about the likelihood of atrocities or violence.
Passive reporting systems such as VAERS and GSK's have a number of strengths, including their broad scope and timely reporting.
Our review identified a total of 10 published studies that included 5 population-based studies [ 16- 20] and 5 passive reporting studies [ 13, 23- 25, 28].
Passive reporting systems for collecting information on NHP-related ADRs cannot be effective if consumers who experience NHP-related ADRs do not report their experiences.
Therefore, 2 groups were created: 1) 150 active reporting sites based in hospital clinical neurology units or neurology practices and 2) 2,494 passive reporting neurologists identified through the deduplicated physician list.
Post-market surveillance in the USA relies on a passive reporting system, and thus adverse events are under-reported, particularly by physicians and hospitals.
"The passive reporting of adverse events is a weak system," Marcia Crosse, the director for health care at the accountability office, said in an interview.
Background: The federally administered Vaccine Adverse Event Reporting System (VAERS) is a passive reporting system that receives domestic and foreign reports of adverse events that occur following immunization.
