Epidemic Waves, Small Worlds and Targeted Vaccination

TL;DR

This paper uses a network model to study how social behavior and connectivity influence disease spread, revealing that targeted vaccination of key areas can effectively eradicate infections.

Contribution

It introduces a network-based model highlighting the role of social structure and focal areas in disease dynamics and control strategies.

Findings

Long-term oscillations depend on social behavior and network structure.

Circular infection waves can be generated in small-world networks.

Targeted vaccination of focal areas effectively eradicates the disease.

Abstract

The success of an infectious disease to invade a population is strongly controlled by the population's specific connectivity structure. Here a network model is presented as an aid in understanding the role of social behavior and heterogeneous connectivity in determining the spatio-temporal patterns of disease dynamics. We explore the controversial origins of long-term recurrent oscillations believed to be characteristic to diseases that have a period of temporary immunity after infection. In particular, we focus on sexually transmitted diseases such as syphilis, where this controversy is currently under review. Although temporary immunity plays a key role, it is found that in realistic small-world networks, the social and sexual behavior of individuals also has great influence in generating long-term cycles. The model generates circular waves of infection with unusual spatial dynamics that depend on focal areas that act as pacemakers in the population. Eradication of the disease can be efficiently achieved by eliminating the pacemakers with a targeted vaccination scheme. A simple difference equation model is derived, that captures the infection dynamics of the network model and gives insights into their origins and their eradication through vaccination.