Dynamical Effects of Homologous Reinfections in a Multi-Strain Dengue Model

The article examines how dengue spreads through multiple viral serotypes, temporary cross-immunity, and antibody-dependent enhancement. Classical models assumed lifelong protection against reinfection with the same serotype, but recent evidence suggests that homologous dengue reinfections can occur, although they are rare. Researchers extended a two-infection model to include homologous reinfections and analyzed their impact on disease transmission dynamics. They found that characteristic features of endemic dengue transmission are reproduced mainly when susceptibility to homologous reinfection is low, meaning reinfections remain rare but dynamically influential. Longer temporary immunity broadens regions of complex oscillatory dynamics, while seasonality changes the bifurcation structure. The results indicate that rare homologous reinfection pathways can influence long-term dengue dynamics and may help explain recurrent epidemics in highly exposed populations.