Comparing the Risk of SARS-CoV-2 Immune Resistance Evolving Across Regions in the Americas with Differing Approaches to Public Health.

Public health policy foundationally impacts how pathogens spread, yet despite multiple pathogens of broader societal concern emerging, little research has examined how policy affects pathogen evolution. To evaluate this connection, we examine how varying public health approaches impact how viral immune susceptibility, including resistance to vaccines, evolves. Integrating evolutionary epidemiological modeling and critical geography, we compare how distinct public health responses early in the COVID-19 pandemic affected the potential evolution of immune evasion in SARS-CoV-2 across four territories: Costa Rica, Panama, Texas, and Uruguay. We use parameter estimates inferred from confirmed case and vaccination time series via stochastic ensemble Kalman filtering in each territory. Our analyses suggest viral immune resistance was most likely to emerge in Texas, which relied almost exclusively on vaccines for disease control. In contrast, regions with comparatively fewer health disparities that also rigorously applied interventions, such as shelter-in-place orders and household support, may have better prevented vaccine resistance from evolving. These comparative analyses highlight the key role policy choices play, potentially representing different governance goals for population health and wellbeing. We argue that such choices impact not only disease spread but also pathogen evolution along epidemiologically critical dimensions like viral immune susceptibility. Our study thus demonstrates how public health priorities drive social-evolutionary feedbacks.