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

Abstract

Objectives: To 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.

Methods: Retrospective nationwide questionnaire surveillance on culture-confirmed GBS infections between 2004 and 2010.

Results: Eighty-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 438359 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.

Conclusions: The 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.