M. Elizabeth Halloran, Emory University

Using Validation Sets for Exposure to Infection and for Outcomes in Vaccine Field Studies

Methods for adjusting for bias in estimates due to mismeasured or missing covariates and outcomes have been developed in many types of health studies. These methods can be used for the efficient design and analysis of vaccine studies as well. Data on exposure to infection can influence estimates of vaccine efficacy, but good data on exposure is difficult to obtain. Non-specific case definitions can lead to very attenuated efficacy estimates, but confirmation by culture of the infectious agent is expensive and difficult. Use of small validation sets can correct the bias of the estimate from the large main study while maintaining efficiency. Using semiparametric methods, we illustrate the use of validation sets for exposure to infection on the example of an HIV vaccine trial. We present initial exploration of the use of validation sets for outcomes in influenza vaccine studies.