Join us for our last annual award of the semester, when Dr. Marie Davidian will deliver a lecture and be presented with the 2021 Marvin Zelen Leadership Award in Statistical Science!
Thursday, May 6, 2021 | 1-2pm
See Seminar & Events page for secure Zoom link
Estimating Vaccine Efficacy Over Time After a Randomized Study is Unblinded
The COVID-19 pandemic due to the novel coronavirus SARS CoV-2 has inspired remarkable breakthroughs in the development of vaccines against the virus and the launch of several phase 3 vaccine trials in Summer 2020 to evaluate vaccine efficacy (VE). Trials of vaccine candidates using mRNA delivery systems developed by Pfizer-BioNTech and Moderna have shown substantial VEs of 94-95\%, leading the US Food and Drug Administration to issue Emergency Use Authorizations and subsequent widespread administration of the vaccines. As the trials continue, a key issue is the possibility that VE may wane over time. Ethical considerations dictate that trial participants be unblinded and those randomized to placebo be offered study vaccine, leading to trial protocol amendments specifying unblinding strategies. Crossover of placebo subjects to vaccine complicates inference on waning of VE. We focus on the particular features of the Moderna trial and propose a statistical framework based on a potential outcomes formulation within which we develop methods for inference on potential waning of VE over time and estimation of VE at any post-vaccination time. The framework clarifies assumptions made regarding individual- and population-level phenomena and acknowledges the possibility that subjects who are more or less likely to become infected may be crossed over to vaccine differentially over time. The principles of the of the framework adapted straightforwardly to other trials. Internationally acclaimed biostatistician.
Dr. Marie Davidian is the J. Stuart Hunter Distinguished Professor of Statistics ate North Carolina State University.
She has distinguished herself through her groundbreaking research focusing on the development of new statistical methods to support precision medicine discovery. She has dedicated her career to addressing emerging challenges in the health sciences while generously serving the statistical community and passionately mentoring the next generation of scientists in the field.
See website for Dr. Davidian’s career highlights.