Invasive Meningococcal Disease in Australian Children 2016–2022: A Multicenter, Prospective Surveillance Study of Serogroup Distribution and Clinical Presentation in the Meningococcal Vaccine Era

BACKGROUND: Although uncommon, invasive meningococcal disease (IMD) results in death in 5%-10% of cases in healthy children and adolescents. This study aimed to examine demographics, clinical presentation, treatment and outcomes of Australian children hospitalized with IMD during the introduction of the meningococcal vaccine program, overall and by serogroup/disease severity. METHODS: This prospective, multicenter study was conducted through the Paediatric Active Enhanced Disease Surveillance network across 8 tertiary pediatric hospitals in Australia. Children 0-18 years of age with laboratory-confirmed IMD admitted between July 2016 and June 2022 were included. Clinical data were collected using standardized protocols. Logistic, quantile, negative binomial regression and univariate comparisons were used to compare characteristics by serogroup and to investigate factors associated with disease severity. RESULTS: Among 137 IMD cases included, 56% were male with a median age of 2 years, 37% were Aboriginal/Torres Strait Islander children and over half resided in socioeconomically disadvantaged areas. Meningococcal serogroup B (MenB) accounted for 55% of cases, followed by MenW (28%) and MenY (4%). The case fatality rate was 3%. Antibiotics were administered within 1 hour of presentation in 17% of cases. At discharge, 29% had ongoing sequelae, including scarring, arthritis, limb deformities or amputation. Most MenB cases were unvaccinated against MenB (93%), and only 1 MenY case had prior quadrivalent polysaccharide vaccination. CONCLUSIONS: This study highlights the continued burden of MenB disease, particularly among socioeconomically disadvantaged and Aboriginal and Torres Strait Islander children, underscores the importance of earlier recognition and treatment to reduce morbidity and mortality, and emphasizes the need for improving vaccine uptake and vaccine availability.