Integrating between-host transmission and within-host immunity to analyze the impact of varicella vaccination on zoster

• Main Authors: Benson Ogunjimi, Lander Willem, Philippe Beutels, Niel Hens
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2015-07-01
• Series: eLife
• Subjects: varicella; zoster; shingles; vaccination; boosting; modeling
• Online Access: https://elifesciences.org/articles/07116

Varicella-zoster virus (VZV) causes chickenpox and reactivation of latent VZV causes herpes zoster (HZ). VZV reactivation is subject to the opposing mechanisms of declining and boosted VZV-specific cellular mediated immunity (CMI). A reduction in exogenous re-exposure ‘opportunities’ through universal chickenpox vaccination could therefore lead to an increase in HZ incidence. We present the first individual-based model that integrates within-host data on VZV-CMI and between-host transmission data to simulate HZ incidence. This model allows estimating currently unknown pivotal biomedical parameters, including the duration of exogenous boosting at 2 years, with a peak threefold to fourfold increase of VZV-CMI; the VZV weekly reactivation probability at 5% and VZV subclinical reactivation having no effect on VZV-CMI. A 100% effective chickenpox vaccine given to 1 year olds would cause a 1.75 times peak increase in HZ 31 years after implementation. This increase is predicted to occur mainly in younger age groups than is currently assumed.