Abstract:
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Clinical case definitions often struggle to satisfy two challenging and potentially conflicting needs - sensitivity and specificity. Diagnostic tests to confirm a case are rarely completely accurate and sometime it is difficult to select a primary diagnostic test for the efficacy trial. Such imperfect sensitivity and specificity will have an impact, in some occasions very substantial, on the expected vaccine efficacy and also study duration to accumulate required number of cases. In most of these situations, the vaccine efficacy will be underestimated. However, the impact on the study duration is unclear. In this study, we investigated the effect from the imperfect sensitivity and specificity on the power and sample size for the vaccine efficacy trial design. A case study of vaccine efficacy trial will be discussed and general recommendation for assay choice will be proposed.
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