Ethan Ashby

Ethan Ashby

Biostatistics PhD Student, University of Washington

Publications

You can also find my articles on my Google Scholar profile

Debiasing hazard-based, time-varying vaccine effects using vaccine-irrelevant infections: An observational extension of a pivotal Phase 3 COVID-19 vaccine efficacy trial

Published in ArXiv, 2025

Time-varying hazard ratios are popular tools to evaluate how vaccine effects vary over time. We explore how to use negative control infections to remove inherent bias in these estimates.

Recommended citation: Ashby, Ethan, et al. (2025). "Debiasing hazard-based, time-varying vaccine effects using vaccine-irrelevant infections: An observational extension of a pivotal Phase 3 COVID-19 vaccine efficacy trial." ArXiv. https://arxiv.org/abs/2511.15099

Validating and Leveraging Non-SARS-CoV-2 Respiratory Infection as a Negative Control Outcome in a Phase 3 COVID-19 Vaccine Trial with Extended Observational Follow-Up

Published in American Journal of Epidemiology, 2025

Irrelevant infection endpoints confirmed as a valid negative control for COVID-19 and are leveraged to detect bias in hazard-based, time-varying vaccine efficacy estimates.

Recommended citation: Ashby, Ethan, et al. (2025). "Validating and Leveraging Non-SARS-CoV-2 Respiratory Infection as a Negative Control Outcome in a Phase 3 COVID-19 Vaccine Trial with Extended Observational Follow-Up." American Journal of Epidemiology. https://academic-oup-com.offcampus.lib.washington.edu/aje/advance-article/doi/10.1093/aje/kwaf176/8239036?utm_source=advanceaccess&utm_campaign=aje&utm_medium=email

Negative Control Outcome Adjustment in Early-Phase Randomized Trials: Estimating Vaccine Effects on Immune Responses in HIV Exposed Uninfected Infants

Published in Statistics in Medicine, 2025

Adjustment for off-target endpoints can improve the efficiency of early-phase randomized trials.

Recommended citation: Ashby, Ethan, et al. (2025). "Negative Control Outcome Adjustment in Early-Phase Randomized Trials: Estimating Vaccine Effects on Immune Responses in HIV Exposed Uninfected Infants." Statistics in Medicine. https://onlinelibrary.wiley.com/doi/10.1002/sim.70142

Chemical Inhibition of Bromodomain Proteins in Insect-Stage African Trypanosomes Perturbs Silencing of the Variant Surface Glycoprotein Repertoire and Results in Widespread Changes in the Transcriptome

Published in Microbiology Spectrum, 2023

Investigating time-course transcriptional response to Bdf3 inhibition in the parasite that causes sleeping sickness.

Recommended citation: Ashby, Ethan C. (2023). "Chemical Inhibition of Bromodomain Proteins in Insect-Stage African Trypanosomes Perturbs Silencing of the Variant Surface Glycoprotein Repertoire and Results in Widespread Changes in the Transcriptome." Microbiology Spectrum. 1(1). https://journals.asm.org/doi/full/10.1128/spectrum.00147-23

Genomic Occupancy of the Bromodomain Protein Bdf3 Is Dynamic during Differentiation of African Trypanosomes from Bloodstream to Procyclic Forms

Published in MSphere, 2022

Cut&Run data analysis demonstrates Bdf3 protein occupancy changes at different sites on the T. brucei genome.

Recommended citation: Ashby, Ethan, et al. (2022). "Genomic Occupancy of the Bromodomain Protein Bdf3 Is Dynamic during Differentiation of African Trypanosomes from Bloodstream to Procyclic Forms." MSphere . 7(3). https://journals.asm.org/doi/full/10.1128/msphere.00023-22

Miscellaneous