Description of selected prospective longitudinal studies on VZV-immunity post exposure and other selected studies.

RE re-exposed; CP chickenpox; CO controls; VZV varicella-zoster virus; RIA radioimmunoassay; PBMC peripheral blood mononuclear cells; TT tetanus toxine; PHA phytohemagglutin; IFN interferon; Cpm counts per minute; FAMA fluorescent antibody to membrane antigen; FCM flow cytometry; ICS intracellular cytokine staining; ELISPOT enzyme-linked immunosorbent spot; GMR geometric mean response; ELISA enzyme-linked immunosorbent assay; RCF responder cell frequency; HCW health-care workers.*H = High: the quality of methods used in this paper permits the results, within the scope of the study design, to be interpreted with at the most a few remarks. M = Medium: the quality of methods used in this paper permits the results, within the scope of the study design, to be interpreted, but with some caution. L = Low: the quality of methods used in this paper urges the reader to interpret the results, even within the scope of the study design, with sufficient caution.£See Table S2.**The ‘B’ statement expresses whether the study supported the existence of exogenous boosting (‘+) or not (‘−’).