Incidence and serotype distribution of invasive group B streptococcal disease in young infants: a multi-country observational study

Background Group B Streptococcus (GBS) is a leading cause of serious infection in very young infants. Robust incidence data from many geographic regions, including Latin America and Asia, are however lacking. Methods A multicenter, hospital-based observational study was performed in Panama, Dominican Republic, Hong Kong and Bangladesh. All represented urban, tertiary referral hospitals, except Bangladesh. GBS cases (microbiological isolation from normally sterile sites in infants aged 0–89 days) were collected over 12 months. Results At 2.35 (95 % CI: 1.74–3.18) cases per 1000 live births, the incidence of early onset GBS disease (EOD) was highest in the Dominican Republic, compared with 0.76 (95 % CI: 0.41–1.39) in Hong Kong and 0.77 (95 % CI: 0.44–1.35) in Panama, while no cases were identified in Bangladesh. Over 90 % of EOD cases occurred on the first day of life, with case fatality ratios ranging from 6.7 % to 40 %, varying by center, age of onset and clinical presentation. Overall, 90 % of GBS (EOD and late onset disease) was due to serotypes Ia, Ib and III. Conclusions The incidence rate of early onset GBS infection reported in Dominican Republic was not dissimilar from that described in the United States prior to screening and intrapartum antibiotic prophylaxis, while the incidence in Hong Kong was higher than previously reported in the Asian region. The failure to identify GBS cases in Bangladesh highlights a need to better understand the contribution of population, healthcare and surveillance practice to variation in reported incidence. Overall, the identified disease burden and serotype distribution support the need for effective prevention methods in these populations, and the need for community based surveillance studies in rural areas where access to healthcare may be challenging.