Abstract
Acute meningitis has a high case-fatality rate and survivors can have severe lifelong disability. We aimed to provide a comprehensive assessment of the levels and trends of global meningitis burden that could help to guide introduction, continuation, and ongoing development of vaccines and treatment programs.
Methods
The Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 study estimated meningitis burden due to one of four types of cause: pneumococcal, meningococcal, Haemophilus influenzae type b, and a residual category of other causes. Cause-specific mortality estimates were generated via cause of death ensemble modeling of vital registration and verbal autopsy data that were subject to standardized data processing algorithms. Deaths were multiplied by the GBD standard life expectancy at age of death to estimate years of life lost, the mortality component of disability-adjusted life years (DALYs). A systematic analysis of relevant publications and hospital and claims data was used to estimate meningitis incidence via a Bayesian meta-regression tool. Meningitis deaths and cases were split between causes with meta-regressions of etiological proportions of mortality and incidence, respectively. Probabilities of long-term impairment by cause of meningitis were applied to survivors and used to estimate years of life lived with disability (YLDs). We assessed the relationship between burden metrics and Socio-demographic Index (SDI), a composite measure of development based on fertility, income, and education.
Findings
Global meningitis deaths decreased by 21.0% from 1990 to 2016, from 403,012 (95% uncertainty interval [UI] 319,426–458,514) to 318,400 (265,218–408,705). Incident cases globally increased from 2.50 million (95% UI 2.19–2.91) in 1990 to 2.82 million (2.46–3.31) in 2016. Meningitis mortality and incidence were closely related to SDI. The highest mortality rates and incidence rates were found in the peri-Sahelian countries that comprise the African meningitis belt, with six of the 10 countries with the largest number of cases and deaths being located within this region. Haemophilus influenzae type b was the most common cause of incident meningitis in 1990, at 780,070 cases (95% UI 613,585–978,219) globally, but decreased the most (–49.1%) to become the least common cause in 2016, with 397,297 cases (291,076–533,662). Meningococcus was the leading cause of meningitis mortality in 1990 (192,833 deaths [95% UI 153,358–221,503] globally), whereas other meningitis was the leading cause for both deaths (136,423 [112,682–178,022]) and incident cases (1.25 million [1.06–1.49]) in 2016. Pneumococcus caused the largest number of YLDs (634,458 [444,787–839,749]) in 2016, owing to its more severe long-term effects on survivors. Globally in 2016, 1.48 million (1.04–1.96) YLDs were due to meningitis compared with 21.87 million (18.20–28.28) DALYs, indicating that the contribution of mortality to meningitis burden is far greater than the contribution of disabling outcomes.
Interpretation
Meningitis burden remains high and progress lags substantially behind that of other vaccine-preventable diseases. Particular attention should be given to developing vaccines with broader coverage against the causes of meningitis, making these vaccines affordable in the most affected countries, improving vaccine uptake, improving access to low-cost diagnostics and therapeutics, and improving support for disabled survivors. Substantial uncertainty remains around pathogenic causes and risk factors for meningitis. Ongoing, active cause-specific surveillance of meningitis is crucial to continue and to improve monitoring of meningitis burdens and trends throughout the world.
