Early-onset and late-onset group B streptococcal disease in Japan: a nationwide surveillance study, 2004–2010

SummaryObjectivesTo clarify the incidence and prognosis of early-onset (EOD) and late-onset (LOD) GBS disease in Japan. To evaluate the influence of national guidelines issued in 2008 on the epidemiology of GBS disease.MethodsRetrospective nationwide questionnaire surveillance on culture-confirmed GBS infections between 2004 and 2010.ResultsEighty-eight EOD and 162 LOD cases were reported from 152 participating hospitals. The case fatality of EOD was 13.6% and of LOD was 8.0%. Premature birth <37 weeks (p < 0.001) and low birth weight <2500 g (p < 0.001) were significantly associated with EOD mortality. A high rate of neurological sequelae was noted in meningitis in EOD (8/24) and LOD (29/85) cases. Based on a live-birth number of 438 359 and inborn case numbers of 36 EOD and 42 LOD, the incidence of EOD and LOD were estimated to be 0.08 (95% confidence interval (CI) 0.06–0.11)/1000 and 0.10 (95% CI 0.07–0.12)/1000 live-births, respectively. Before (2004–2008) and after (2009–2010) the issue of guidelines, the mortality of EOD (from 14.8% to 11.8%) and LOD (from 9.8% to 2.5%) improved, but the incidence was unchanged.ConclusionsThe incidence of EOD and LOD is apparently low in Japan, but the mortality and morbidity rates remain substantial. The issue of national guidelines did not affect the incidence.