Ethan Ashby, a PhD student in Biostatistics PhD at the University of Washington, has received a Distinguished Student Paper Award from the International Biometric Society Eastern North American Region (ENAR) for his paper, “Debiasing hazard-based estimates of time-varying vaccine effects using vaccine-irrelevant infections: An application to an observational extension of a Phase 3 COVID-19 vaccine efficacy trial.”
“Reliable estimation of how vaccine effectiveness wanes over time is important for evaluating new vaccines and informing when boosters should be offered to vulnerable populations,” said Ashby.
“However, estimating time-varying vaccine effects is challenging because vaccine protection alters who remains at risk of disease over time, inducing selection bias in cohorts of disease-free participants. As a result, naive estimates of time-varying vaccine effectiveness can become systematically distorted and yield spurious evidence of waning."
Ashby says their work proposes a principled strategy to remove hidden bias and recover reliable inference on time-varying vaccine effectiveness curves using irrelevant infection endpoints, which can be routinely collected through surveillance in vaccine studies.
“We hope that this work provides a roadmap to obtain more robust evidence of vaccine effectiveness durability to inform public health decision-making," said Ashby.
Ashby will be recognized during the ENAR 2026 Spring Meeting Presidential Invited Address on March 17, 2026.
