Development of an Early-Phase Local Model for Pandemics Using Public Health Data: Application to the COVID-19...

The emergence of novel infectious pathogens challenges early-phase modeling of disease transmission due to limited, low-quality data and an incomplete understanding of the pathogen. Additionally, regional variations in outbreaks necessitate models that incorporate local dynamics. We present an early-phase local model that leverages constrained public health data, primarily infection counts and aggregated regional characteristics, to study disease transmission dynamics. To address data limitations and potential model misspecifications, we incorporate a quasi-likelihood approach with a flexible error term. Furthermore, we introduce an online estimator that enables real-time data updates, supported by an iterative algorithm for parameter estimation. We applied this method to early COVID-19 data, analyzing infection counts and county-level risk factors from more than 800 U.S. counties to predict disease spread and assess the impact of social behavior, demographics, and vaccination coverage on disease transmission. This framework improves early outbreak analysis and informs local pandemic response under suboptimal data conditions.