Use of National Health Insurance database to evaluate the impact of public varicella vaccination program on burden of varicella in Taiwan.

The aims of this study were to investigate the epidemiology of varicella and evaluate the effect of varicella vaccination on the burden of varicella in Taiwan. The outpatient and hospitalization claims made to the National Health Insurance (NHI) in public and private vaccination areas were compared during 2000-2002. In 2002, the outpatient visit rates for 1- to 5-year-old children in public vaccination areas were 66-78% lower than their counterparts in private vaccination areas. The reduction in outpatient visit rate was the greatest among preschool children. The reductions also occurred in every age group including infants and adults. This study showed significant evidence of vaccine impact with a marked decline in clinical cases in the short term.