In Japan, herpes zoster is not monitored officially or nationwide. Recently,\nthe databases of all electronic medical claims nationwide (NDBEMC) have\nbeen available for research. We use NDBEMC from April 2011 to March\n2015. To evaluate the effects of initiation of routine immunization for varicella\nin children, we regressed the number of herpes zoster patients on the\ndummy variable for the routine immunization for varicella in children with\nand without a linear time trend. The estimated coefficient for the routine\nimmunization for varicella was 0.5157 and its p-value was 0.001. However, if\nthe time trend was added as an explanatory variable, the estimated coefficient\nfor the routine immunization for varicella changed to be -0.039 and its\np-value was 0.384. It means that the routine immunization for varicella was\n7.8% higher after introduction than before. However, it was presumed to reflect\nsuch an upward trend.
Loading....