Immunization coverage and natural infection rates of vaccine-preventable diseases among children by questionnaire survey in 2005 in Japan.

We performed questionnaire survey in 2005, just before the introduction of the MR vaccine, concerning child vaccination and/or infection history for measles, mumps, rubella, varicella, influenza, diphtheria-pertussis-tetanus (DPT), BCG, and Japanese encephalitis. The vaccination rate against measles and rubella did not exceed 95% at any age levels. As a result, children who had contracted measles and/or rubella were observed at all age levels. The vaccination rate was 95% or higher only for BCG and DPT. The vaccination rates for influenza, mumps, and varicella, although vaccination against which diseases was being performed voluntarily, were low, and outbreaks of these diseases were expected to persist. The vaccination rates at a low level for these infectious diseases might be one of the most possible risk factors to the high prevalence of the diseases in nursery schools (daycare centers), kindergartens, and elementary schools all over Japan.