Samantha Bents
PhD Candidate, Stanford University
The CEIRR CMC holds bi-monthly research seminars that feature leading researchers who develop state-of-the-art computational methods to better understand respiratory viruses. These events are designed to facilitate in-depth discussions and provide ample opportunity for questions from the audience, with each seminar lasting 1 hour and 30 minutes.
Title: Unraveling the Mechanisms of Endemic Respiratory Pathogen Dynamics in the Wake of the COVID-19 Pandemic
Vaccine effectiveness (VE) estimates can vary widely between years and populations, even for the same vaccine. VE is known to be sensitive to susceptible depletion and differences in pre-vaccination infection risk between vaccinated and unvaccinated populations. However, how variation in pre-vaccination risk within and between the two groups affects VE over time remains unclear. This uncertainty is especially important given observations of negative VE. We investigated the difference between VE and true vaccine protection considering continuous distributions of pre-vaccination infection risk under three scenarios. When the vaccinated and unvaccinated populations differ in their mean risk, VE can be higher or lower than true vaccine protection. Similar patterns arise when the two populations share identical means but different distributions of risk. Finally, if infection-derived immunity lasts longer than vaccine protection, annual VE estimates can vary by tens of percentage points between years despite constant true vaccine protection. These theoretical results underscore that VE measures a vaccination program’s performance in a particular population and period of time, and VE can vary counterintuitively between years and populations even when vaccine-induced protection is constant. Explaining variability in VE thus requires a more complete understanding of populations’ distributions of infection risk.
After you register, click on the Eventbrite event page for a zoom link.
Note: CEIRR CMC events are open only to CEIRR participants. The meeting and discussion are confidential.