Background: Universal varicella vaccination for 1-year-old children was introduced in Germany in 2004. We investigated changes in the incidence and type of varicella-associated neurologic complications in children during the first 7 years after universal vaccination recommendation.
Methods: A surveillance study was conducted based on patients <17 years of age with an International Classification of Diseases (10th Revision) discharge diagnosis of varicella, annually reported by 22-29 pediatric hospitals in Bavaria, Germany, 2005 to 2011. Annual incidences were estimated and linear trend across years was assessed by Poisson regression models.
Results: Of a total of 1263 varicella-associated pediatric hospitalizations, 228 children (18.1%) had neurologic complications (median age 4 years, interquartile range 2-7; 56% male). The most frequent neurologic complications were febrile convulsion (32.0% of 228 children, median age 3.0 years), varicella encephalitis or meningitis (28.9%; median age 4.5 years), syncope (13.2%; median age 7.0 years) and cerebral convulsion (11.0%; median age 4.0 years). Other complications included ataxia (3.1%), facial nerve palsy (2.6%) and cerebral vasculitis/infarction (1.8%). Neurologic complications showed a continuous decrease between 2005 and 2011, from an incidence of 2.8 (95% confidence interval: 2.1-3.6) per 100,000 children <17 years of age to 1.2 (95% confidence interval: 0.7-2.1; P < 0.001). In particular, a marked decline was observed among children up to 7 years of age, mainly because of a decrease in the number of febrile convulsions and encephalitis or meningitis.
Conclusion: The incidence of varicella-associated neurologic complications in children decreased approximately by 60% during the first 7 years following the recommendation for universal vaccination.