 This review updates a 2013 systematic literature review of 40 studies related to exogenous boosting, e.b., hypothesis, which posits that cell-mediated immunity is boosted for individuals re-exposed to varicellizoster virus, VZV. The updated review identifies an additional 41 studies, 22 observational, and 19 modeling studies. Observational analyses generally reported pre-UVV increases in HZ incidents, making it difficult to attribute post-UVV increases to UVV versus other causes. Modeling studies considered a range of e.b. frameworks, from no boosting to full permanent immunity. Mathematical modeling efforts are needed in countries with long-standing vaccination programs to capture the dynamics of VZV transmission and temporal changes that may affect HZ incidents. Use of real-world pre-dash, the post-vaccination data on varicella, and HZ incidents to validate model predictions may improve approaches to e.b. parameterization and understanding of the effects of varicella vaccination programs. This article was authored by Sandra E. Talberg, Elizabeth M. La, Josephine Morskopf, and others. We are article.tv, links in the description below.