Right sizing for vaccine effectiveness studies: how many is enough for reliable estimation?
Olivia H Price, Kylie S Carville, Sheena G Sullivan
COMMUNICABLE DISEASES INTELLIGENCE | AUSTRALIAN GOVERNMENT, DEPT HEALTH & AGEING | Published : 2019
Background: The precision of vaccine effectiveness (VE) estimates is dependent on sample size and sampling methods. In Victoria, participating general practitioners (GPs) are not limited by the number of influenza-like illness (ILI) patients they collect respiratory samples (swabs) from in sentinel surveillance. However, in the context of scarce resources it is of interest to determine the minimum sample size needed for reliable estimates. Methods: Following the test-negative design, patients with ILI were recruited by GPs and tested for influenza. Descriptive analyses were conducted to assess possible selection bias introduced by GPs. VE was calculated by logistic regression as [1 – odds ra..View full abstract
We thank the general practitioners, nurse practitioners and practice staff that participated and contributed to VicSPIN. VicSPIN is supported by the Victorian Department of Health and Human Services. The WHO Collaborating Centre for Reference and Research on Influenza is supported by the Australian Government Department of Health.