Trends in herpes zoster epidemiology in Germany based on primary care sentinel surveillance data, 2005-2016

Herpes zoster (HZ) is caused by reactivation of the varicella-zoster-virus (VZV). Childhood varicella vaccination, as recommended in Germany in 2004, may reduce the risk of HZ in vaccinated children but also virus circulation and thus the booster possibility of latent infected persons. In this context we analyzed age-specific trends in HZ epidemiology in Germany using data on HZ-associated outpatient consultations in participating sentinel sites and HZ-associated cases in all hospitals since 2005. We analyzed two separate time periods that differed in sentinel management and data integrity. For the period 2005-2010, we found a decrease in HZ-associated outpatient consultations in 1- to 4-year-olds (IRR = 0.72, 95%CI 0.63-0.81, p<0.001). For the period 2013-2016, we observed a decrease in HZ-associated outpatient consultations in 10- to 14-year-olds (IRR = 0.85, 95%CI 0.78-0.93, p<0.01). Moreover, we detected an increase in the age groups 20 years and older except for the group 30-39 years. HZ-associated hospitalizations showed similar trends for the second time period (here 2012-2015). The decrease in HZ-associated outpatient consultations and hospitalizations in children started and continued over cohorts eligible for varicella vaccination and could be a result of their reduced HZ-risk. Whether the observed steady increasing HZ incidences for adults are associated with the varicella vaccination in children remains unclear and could not be investigated with our data.