Background The early-onset sepsis calculator (EOSC) reduces unnecessary antibiotic treatment in newborns. However, its performance in identifying cases with early-onset disease (EOD) is unclear. We compared the sensitivity of the EOSC to the current Dutch and National Institute for Health and Care Excellence (NICE) guidelines when applied to a cohort of newborns with culture-positive early-onset sepsis and meningitis.Methods Culture-positive Streptococcus agalactiae (GBS) and Escherichia coli (E. coli) sepsis and meningitis patients ≤3 days old with a gestational age ≥34 weeks, identified between 1/1/2018 and 31/1/2021 in a Dutch prospective nationwide cohort study were included. Cases were identified by treating physicians and microbiological surveillance. Primary outcome was the proportion of patients that would have been treated according to the EOSC, the Dutch, and the NICE EOD prevention guidelines. Differences between proportions were analysed using McNemar's test.Findings We included 81 GBS and 7 E. coli EOD cases. At 4 h after birth, the EOSC would have recommended antibiotic treatment in 32 (36%) patients, compared to 44 (50%) by the Dutch (p<0¢01) and 48 (55%) by the NICE guideline (p<0¢01). The EOSC would have initially recommended routine care for 52% of patients compared to 31% and 30% for the Dutch and NICE guidelines (p<0¢01). At 24 h after birth, the EOSC would have recommended antibiotic treatment in 54 (61%) infants compared to 64 (73%) by the Dutch (p = 0¢02) and 63 (72%) by the NICE guidelines (p = 0¢06).Interpretation The sensitivity of the EOSC in identifying cases of EOD is lower compared to both Dutch and NICE guidelines, especially directly after birth. The EOSC relies more on clinical symptoms and results in less overtreatment of healthy newborns at the cost of later antibiotic treatment in initially well-appearing EOD patients.

Background Preterm birth and neonatal infections are both associated with mortality and long-term neurodevelopmental impairments (NDI). We examined whether the effect of invasive group B streptococcus disease (iGBS) on mortality and long-term NDI differs for preterm and term infants, and whether co-occurrence of iGBS and prematurity leads to worse outcome. Methods Two nationwide cohort studies of children with a history of iGBS were conducted using Danish and Dutch medical and administrative databases. Comparison cohorts of children without iGBS were matched on birth year/month, sex and gestational age. Effects of iGBS on all-cause mortality and NDI were analyzed using Cox proportional hazards and logistic regression, respectively. Potential effect modification by prematurity was evaluated on additive and multiplicative scales. Results We identified 487 preterm and 1,642 term children with a history of iGBS and 21,172 matched comparators. Dutch preterm children exposed to iGBS had the highest mortality rate by 3 months of age (671/1000 person-years [95% confidence interval 412-929/1000 person-years]). ~30% of this mortality rate could be due to the common effect of iGBS and prematurity. Preterm children with iGBS had the highest NDI risk (8.8% in Denmark; 9.0% in the Netherlands). 36% of this NDI risk in Denmark and 60% of this risk in The Netherlands might be due to the combined effect of iGBS and prematurity. Conclusion Prematurity is associated with iGBS development, and our study shows that it also negatively impacts outcomes of children who survive iGBS. Preterm babies would benefit from additional approaches to prevent GBS colonization, as this decreases the risk of both preterm birth and iGBS.