Abstract
INTRODUCTION: Infants have the highest incidence of meningococcal meningitis (MM) among all age groups in China. Infants receive their first and second doses of serogroup A meningococcal polysaccharide vaccine at 6 and 9 months of age. METHODS: We extracted data on MM cases among 0-11-month-old children reported during 2006-2023 from the National Notifiable Diseases Registry System and the National Meningococcal Disease Surveillance System and conducted an epidemiological and clinical analysis. RESULTS: During the study period, 721 infant MM cases were reported. Incidence decreased from 7.31 cases per million to 2.74 per million, while the all-age incidence declined from 1.27 cases per million to 0.06 per million. Among 210 cases with serogrouping results, five serogroups (A, B, C, W, Y) and non-groupable strains were detected. Serogroup A cases decreased from 36.36% to 1.87% during the study period, while serogroup B increased from 14.55% to 67.29%. Fever, nausea, and/or vomiting were common symptoms across all serogroups. The frequencies of petechiae and/or purpura in serogroup A (73%) and C (92%) were substantially higher than in other serogroups. Among serogroup B cases, 26.42% developed petechiae and/or purpura, 26.42% exhibited neck stiffness, and 13.21% had positive Kernig's and/or Brudzinski's signs. CONCLUSIONS: The incidence of MM in infants has significantly decreased but remains higher than incidence across all age groups. Serogroup B cases were the most common. Atypical symptoms in infant cases challenge timely diagnosis. We suggest eligible infants receive meningococcal vaccination timely, and the development of serogroup B meningococcal vaccines should be accelerated.