Systematic review of the evidence on the epidemiology of herpes zoster: incidence in the general population and specific subpopulations in Spain.

Objectives: Herpes zoster (HZ) is an important cause of morbidity around the world, especially among the adult population aged >50 years.

Study Design: A systematic review of the literature (up to October 31, 2016) was performed to identify available evidence on incidence of HZ in the general population and in a specific subpopulation in Spain.

Methods: PubMed and Embase databases were searched, combining the following search terms: 'herpes zoster', 'diabetes mellitus (DM)', 'chronic obstructive pulmonary disease (COPD)', 'chronic heart failure', 'mental disorders' and 'immunocompromised'. Supplements for local scientific congresses, non-indexed Spanish journals and official epidemiological reports, potentially HZ related, were also manually searched. The inclusion criteria were the following: English or Spanish publications reporting incidence of HZ in the Spanish general population and/or specific subpopulations. No restrictions were applied on the study design or population age.

Results: Among 269 references retrieved (48 PubMed, 148 Embase and 73 manual searching), 34 were finally included. Incidence of HZ in the general population ranged from 2.1 to 5.5/1000 person-years. HZ incidence ranged from 9.4 to 15.3/1000 patients with DM and from 11.0 to 11.4/1000 population with COPD or cardiovascular disease. In asthmatic patients, 6.9 HZ cases/1000 subjects were reported. The highest HZ incidence (1.3-400.0/1000 person-years) was in immunocompromised persons (10.0/1000 patients with cancer, 12.5/1000 patients with AIDS, from 5.0 to 240.0/1000 transplanted patients and from 6.6 to 27.0/1000 population with rheumatic diseases). Three studies estimated an increased risk of HZ in comparison with general population, for patients with DM (24%), COPD (39%) and COPD receiving inhaled corticosteroids (61%).

Conclusions: The results suggest a high risk of HZ in certain age groups and specific subpopulations. This study could contribute to identify target age populations and at-risk groups if implementation of HZ vaccination programmes in Spain would be considered.