Epidemiology of invasive Haemophilus influenzae type b disease in Singapore children, 1994–2003

Global Case Fatality of Bacterial Meningitis During an 80-Year Period: A Systematic Review and Meta-Analysis

Importance

The impact of vaccination, antibiotics, and anti-inflammatory treatment on pathogen distribution and outcome of bacterial meningitis over the past century is uncertain.

Objective

To describe worldwide pathogen distribution and case fatality ratios of community-acquired bacterial meningitis.

Data Sources

Google Scholar and MEDLINE were searched in January 2022 using the search terms bacterial meningitis and mortality.

Study Selection

Included studies reported at least 10 patients with bacterial meningitis and survival status. Studies that selected participants by a specific risk factor, had a mean observation period before 1940, or had more than 10% of patients with health care-associated meningitis, tuberculous meningitis, or missing outcome were excluded.

Data Extraction and Synthesis

Data were extracted by 1 author and verified by a second author. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Random-effects models stratified by age (ie, neonates, children, adults), Human Development Index (ie, low-income or high-income countries), and decade and meta-regression using the study period's year as an estimator variable were used.

Main Outcome and Measure

Case fatality ratios of bacterial meningitis.

Results

This review included 371 studies performed in 108 countries from January 1, 1935, to December 31, 2019, describing 157 656 episodes. Of the 33 295 episodes for which the patients' sex was reported, 13 452 (40%) occurred in females. Causative pathogens were reported in 104 598 episodes with Neisseria meningitidis in 26 344 (25%) episodes, Streptococcus pneumoniae in 26 035 (25%) episodes, Haemophilus influenzae in 22 722 (22%), other bacteria in 19 161 (18%) episodes, and unidentified pathogen in 10 336 (10%) episodes. The overall case fatality ratio was 18% (95% CI, 16%-19%), decreasing from 32% (95% CI, 24%-40%) before 1961 to 15% (95% CI, 12%-19%) after 2010. It was highest in meningitis caused by Listeria monocytogenes at 27% (95% CI, 24%-31%) and pneumococci at 24% (95% CI, 22%-26%), compared with meningitis caused by meningococci at 9% (95% CI, 8%-10%) or H influenzae at 11% (95% CI, 10%-13%). Meta-regression showed decreasing case fatality ratios overall and stratified by S pneumoniae, Escherichia coli, or Streptococcus agalactiae (P < .001).

Conclusions and Relevance

In this meta-analysis with meta-regression, declining case fatality ratios of community-acquired bacterial meningitis throughout the last century were observed, but a high burden of disease remained.

A systematic review and critical evaluation of invasive Haemophilus influenzae type B disease burden studies in Asia from the last decade: lessons learned for invasive bacterial disease surveillance

In Asia, questions regarding the burden of Haemophilus influenzae type b (Hib) disease have delayed decision-making on introduction of Hib vaccine. However, over the past decade many studies have been published regarding Hib disease burden in Asia. We conducted a systematic literature review of all reports of Hib disease burden in Asia between 1998 and 2009, and critically reviewed their methods and data quality. We identified 94 studies from 28 countries in Asia presenting data on Hib disease burden. Of the 94 studies reviewed, 49 (52%) used a case definition consistent with World Health Organization standards, and 47 (50%) described laboratory methodology used. Twenty-seven surveillance studies presented data on incidence of Hib disease, with 8 (30%) accounting for missed cases, 6 (15%) accounting for cases with missed diagnostic tests, and 2 (7%) that considered prior antibiotic use. Of the 21 studies that provided incidence data for Hib meningitis, 10 (48%) used active, prospective, population-based surveillance, and found unadjusted incidence rates of Hib meningitis ranging from a low of 0.98 per 100,000 child-years in children aged less than 5 years in China to a high of 28 per 100,000 child-years in children less than 5 years in Mongolia. Of 49 studies that reported the etiology of bacterial meningitis, 30 (60%) identified Hib as the most common cause. This review highlights the importance of using rigorous methodologies, including standardized surveillance methods and appropriate laboratory diagnostic tests, when conducting studies measuring the burden of invasive bacterial diseases including those caused by Hib. When poorly conducted, studies can underestimate disease burden and lead to inappropriate decisions about vaccine introduction.