Estimation of vaccine efficacy for variants that emerge after the placebo group is vaccinated.

ABSTRACT: SARS-CoV-2 continues to evolve and the vaccine efficacy against variants is challenging to estimate. It is now common in phase III vaccine trials to provide vaccine to those randomized to placebo once efficacy has been demonstrated, precluding a direct assessment of placebo controlled vaccine efficacy after placebo vaccination. In this work, we extend methods developed for estimating vaccine efficacy post placebo vaccination to allow variant specific time varying vaccine efficacy, where time is measured since vaccination. The key idea is to infer counterfactual strain specific placebo case counts by using surveillance data that provide the proportions of the different strains. This blending of clinical trial and observational data allows estimation of strain-specific time varying vaccine e

SUBMITTER: Follmann D 

PROVIDER: S-EPMC9111090 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature