O'Sullivan CP, et al. - Researchers sought to determine the burden and clinical features of invasive group B streptococcal disease in infants younger than 90 days in the UK and Ireland, together with the characteristics of disease-causing isolates. They defined early onset as a disease in the first 6 days of life and late onset as 7–89 days of life. In 2014–15, they identified 856 cases of group B streptococcus, an incidence of 0·94 per 1000 livebirths. Incidence for early-onset disease (n=517) was 0·57 per 1000 livebirths, and for late-onset disease (n=339) was 0·37 per 1000 livebirths. Death of 53 infants was reported (case fatality rate 6·2%), of whom 27 had early-onset disease (case fatality rate 5·2%) and 26 had late-onset disease (case fatality rate 7·7%). The predominant serotypes identified were III (241 [60%] of 402 serotyped isolates) and Ia (69 [17%]); five serotypes (Ia, Ib, II, III, V) accounted for 377 (94%) of all serotyped isolates. This study suggests an increase in the incidence of invasive infant group B streptococcal disease in the UK and Ireland since a comparable study done in 2000–01. Despite the introduction of national prevention guidelines, no reduction in the burden of early-onset disease was evident, suggesting the necessity for new strategies for prevention.