Seungjae Byun, Yeongtaek Hwang, Yejun Son, Taelim Choi, Hyeon Jin Kim, Lee Smith, Ho Geol Woo, Christa J Nehs, Dong Keon Yon, Jiseung Kang
The burden of meningitis in the WPR declined substantially from 1990 to 2023, but persistent cross-country inequalities and shifts in age-specific and pathogen-specific patterns remained. Hib3 and PCV3 vaccine introductions were associated with meaningful reductions in vaccine-targeted meningitis mortality, though the effect varied across countries.
BACKGROUND: Meningitis remained a major cause of death and disability worldwide, but evidence on long-term trends, pathogen distribution, and the impacts of the vaccine program across the WHO Western Pacific Region (WPR) remained limited.
METHODS: We used the World Health Organization Immunization Data and the Global Burden of Diseases Study (GBD) 2023 for the period 1990-2023. We assessed the incidence and mortality of meningitis across 32 WPR countries. Incidence and mortality were analyzed by age, sex, and 17 pathogens, with age-standardized rates calculated using the GBD global standard population. To evaluate the impact of the vaccine program, we applied negative binomial generalized linear models with a log link function and population offset to annual pathogen-specific death counts, characterizing vaccine exposure by program introduction and annual coverage.
RESULTS: From 1990 to 2023, incident cases of meningitis in the WPR declined from 638.02 thousand (95% uncertainty interval [UI], 497.54-789.94) to 162.67 thousand (136.19-192.51), and deaths declined from 78.16 thousand (55.76-103.50) to 15.17 thousand (11.45-21.03), although marked between-country disparities persisted. Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae accounted for the greatest number of meningitis-related deaths, although their burden declined over time. Haemophilus influenzae type b (Hib3) introduction was associated with a 31.85% reduction in Haemophilus influenzae meningitis deaths across the WPR (95% CI, -39.40% to -23.35%), and pneumococcal conjugate (PCV3) introduction with an 11.53% reduction in Streptococcus pneumoniae meningitis deaths (95% CI, -21.20% to -0.68%). Under a counterfactual scenario of 95% vaccine coverage, Haemophilus influenzae meningitis deaths were projected to further decline by 14.82% (95% CI, 7.33%-21.41%), and Streptococcus pneumoniae meningitis deaths by 12.27% (2.43%-20.92%).
CONCLUSIONS: The burden of meningitis in the WPR declined substantially from 1990 to 2023, but persistent cross-country inequalities and shifts in age-specific and pathogen-specific patterns remained. Hib3 and PCV3 vaccine introductions were associated with meaningful reductions in vaccine-targeted meningitis mortality, though the effect varied across countries.