Mobility network reveals the impact of geographic vaccination heterogeneity on COVID-19

Abstract

Massive vaccination is one of the most effective epidemic control measures. Because one s vaccination decision is shaped by social processes (e.g., socioeconomic sorting and social contagion), the pattern of vaccine uptake tends to show strong social and geographical heterogeneity, such as urban-rural divide and clustering. Yet, little is known to what extent and how the vaccination heterogeneity affects the course of outbreaks. Here, leveraging the unprecedented availability of data and computational models produced during the COVID-19 pandemic, we investigate two network effects--the hub effect (hubs in the mobility network usually have higher vaccination rates) and the homophily effect (neighboring places tend to have similar vaccination rates). Applying Bayesian deep learning and fine-grained simulations for the U.S., we show that stronger homophily leads to more infections while a stronger hub effect results in fewer cases. Our simulation estimates that these effects have a combined net negative impact on the outcome, increasing the total cases by approximately 10% in the U.S. Inspired by these results, we propose a vaccination campaign strategy that targets a small number of regions to further improve the vaccination rate, which can reduce the number of cases by 20% by only vaccinating an additional 1% of the population according to our simulations. Our results suggest that we must examine the interplay between vaccination patterns and mobility networks beyond the overall vaccination rate, and that the government may need to shift policy focus from overall vaccination rates to geographical vaccination heterogeneity.