Periodicity of varicella-zoster virus in the presence of immune boosting and clinical reinfection with varicella

Abstract

Background: Clinical reinfection with varicella is normally ignored in mathematical transmission models as it is considered too rare to be important. Methods: We apply basic bifurcation analysis to a simple mathematical model of varicella-zoster virus (VZV) transmission incorporating reinfection. Results: We demonstrate that under certain conditions this model can exhibit periodic behaviour as opposed to what is observed in VZV models that ignore the possibility of repeat varicella attacks. Periodicity can be induced by a combination of immune boosting and reinfection while the impact of zoster (shingles) recurrence on the onset of periodicity is negligible. Conclusions: Our results suggest that mathematical models of VZV may benefit from inclusion of repeat varicella.