An Outbreak of Serogroup Y Meningococcal Meningitis in a Private Secondary Vocational School - Guangzhou City, Guangdong Province, China, 2023.

Abstract

The inclusion of meningococcal vaccines in the National Immunization Program (NIP) over several years has significantly reduced the incidence of meningococcal meningitis in China to historic lows. Worldwide, there has been a diversification of meningococcal serogroups, leading to a shift in dominant serogroups in China from serogroup A to serogroups C and B, accompanied by a rise in reports of serogroups Y and W. An outbreak of serogroup Y Neisseria meningitidis (Nm) in a secondary vocational school involved a single confirmed severe case and 24 individuals with laboratory-confirmed Nm carriage. Epidemiological investigation revealed that the outbreak was localized to the classroom of the confirmed case. Prolonged close contact within a confined space was identified as a significant risk factor for Nm transmission. The genotype sequence identified was type 1655 (ST-1655), which is categorized under clonal complex 23 (CC-23) and bears resemblance to 8 previously confirmed cases of serogroup Y meningococcal meningitis within Guangdong Province. This suggests that serogroup Y infections continue to sporadically emerge and have become prevalent strains. This outbreak underscores the critical need to enhance surveillance of meningococcal serogroups and population carrier, and advocate for vaccination with MenY-containing vaccines.