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Activity Number:
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403
- SPAAC Poster Competition
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Type:
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Topic Contributed
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Date/Time:
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Tuesday, July 30, 2019 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Statistics in Epidemiology
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Abstract #306621
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Title:
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Power and Sample Size Considerations for the Test Negative Design
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Author(s):
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Yanan Huo* and Natalie E Dean
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Companies:
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and University of Florida
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Keywords:
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Test Negative Design;
vaccines;
sample size;
score test;
counting process
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Abstract:
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The test negative design (TND) is a recent epidemiological study design used to evaluate vaccine effectiveness. The TND enrolls individuals receiving testing for a target disease as part of routine care. Vaccine effectiveness is estimated from the odds ratio of testing positive for vaccinated versus unvaccinated patients. No guidance is available on sample size and planning for TND studies. The TND is related to case-control studies while sharing similar uncertainties with cross-sectional studies. The Wald test performs poorly in both case-control and TND studies when vaccine effectiveness is high. The variance estimator is unstable when the expected test positive vaccinated cell count is low. Continuity corrections help to stabilize the variance but induce bias. We recommend using a score-based approach to design and analyze TND studies. We examine the likelihood of the TND using stochastic processes to model the underlying data generating mechanism. Where density sampling is assumed, individuals can repeatedly test negative for the target disease prior to testing positive. We recommend strategies to adjust for within-subject correlation due to repeated testing.
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Authors who are presenting talks have a * after their name.
