The Design and Analysis of Seroefficacy Studies for Typhoid Conjugate Vaccines.

ABSTRACT:

Background

Demonstrating the efficacy of new Vi-conjugate typhoid vaccines is challenging, due to the cost of field trials requiring tens of thousands of participants. New trial designs that use serologically defined typhoid infections (seroefficacy trials) rather than blood culture positivity as a study endpoint may be useful to assess efficacy using small trials.

Methods

We developed a model for Vi-immunoglobin G antibody responses to a Vi-vaccine, incorporating decay over time and natural boosting due to endemic exposures. From this, we simulated clinical trials in which 2 blood samples were taken during follow-up and the relative risk of a serologically defined typhoid infection (seroefficacy) was computed. We aimed to determine (1) whether seroefficacy trial designs cou

SUBMITTER: Liu X 

PROVIDER: S-EPMC6405265 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature