Inference of latent epidemic regimes and generative simulations reveal how inequality and mobility shape COVID-19 transmission
摘要
Epidemic waves in large metropolitan areas unfold heterogeneously across territories shaped by persistent socioeconomic inequalities. Explaining how transmission intensifies, stabilises, and shifts across the urban landscape remains a central challenge in epidemiology. This study develops a covariate-dependent, non-homogeneous Hidden Markov Model (nHMM) to infer latent transmission regimes from municipality-level COVID-19 incidence in Santiago, Chile. The framework links daily case dynamics to mobility flows and structural socioeconomic indicators within a hierarchical specification that captures inter-municipal heterogeneity. Model selection identifies three statistically distinct and epidemiologically interpretable regimes corresponding to moderate, severe, and critical transmission phases. Transition dynamics reveal marked spatial asymmetries: while increases in mobility consistently elevate escalation risk, structural conditions—such as overcrowding and deficits in urban infrastructure—substantially influence both the probability of entering and the persistence within high-severity regimes. To ensure epidemiological interpretability, regime-conditioned incidence trajectories are mapped to the time-varying reproduction number (