Group B Streptococcus disease during infancy and risk of subsequent neurodevelopmental impairments in young children: a population-based cohort study in Ontario, Canada

Background — Group B Streptococcus (GBS) is a leading infectious cause of neonatal morbidity and mortality worldwide, yet data on longer-term outcomes in children remain limited. We aimed to assess the risk of neurodevelopmental impairments (NDIs) in GBS survivors and to explore effect modification by sex and prematurity.

Methods — We performed a population-based cohort study of liveborn infants in Ontario between April 2012 and March 2018, using linked birth registry, laboratory, and health administrative databases. GBS disease in the first year of life was ascertained through culture results and diagnostic codes. NDIs, encompassing cognitive, motor, sensory (hearing, vision), and social/behavioural domains, were ascertained up to five years of age using diagnostic codes. Cox regression was used to estimate adjusted hazard ratios (aHR) for overall, domain-specific, and multidomain NDIs, comparing children with and without GBS disease during infancy.

Findings — Of 764,934 infants, 771 had a history of GBS disease. GBS survivors had a twofold increased risk of any NDI (adjusted hazard ratio [aHR]: 2.18 [95% CI: 1.88, 2.54]) and higher rates of cognitive (aHR: 2.79 [95% CI: 2.37, 3.30]), motor (aHR: 7.08 [95% CI: 2.93, 17.08]), social/behavioural (aHR: 1.60 [95% CI: 1.20, 2.14]), and sensory (aHR: 1.64 [95% CI: 1.02, 2.64]) impairments. Male children and those born preterm (<37 weeks) had disproportionately higher risks of GBS-associated NDIs.

Interpretation — GBS disease in infancy is associated with a higher risk of NDIs by age five years, particularly for male children and those born preterm. Primary prevention strategies are needed to mitigate long-term developmental impacts of early-life GBS disease.