Description of selected observational studies on HZ incidence in populations with a widespread chickenpox vaccination program.

HMO health maintenance organization; HZ herpes zoster; CP chickenpox; RR relative risk; PY person-years; MMDS Melbourne Medical Deputising Service; ER emergency room. §Descriptions of vaccination uptake are as reported in the respective original papers. *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 (‘−’).