The Global Landscape of Pediatric Bacterial Meningitis Data Reported to the World Health Organization-Coordinated Invasive Bacterial Vaccine-Preventable Disease Surveillance Network, 2014-2019

Abstract

Background: The World Health Organization (WHO) coordinates the Global Invasive Bacterial Vaccine-Preventable Diseases (IB-VPD) Surveillance Network to support vaccine introduction decisions and use. The network was established to strengthen surveillance and laboratory confirmation of meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.

Methods: Sentinel hospitals report cases of children <5 years of age hospitalized for suspected meningitis. Laboratories report confirmatory testing results and strain characterization tested by polymerase chain reaction. In 2019, the network included 123 laboratories that follow validated, standardized testing and reporting strategies.

Results: From 2014 through 2019, >137 000 suspected meningitis cases were reported by 58 participating countries, with 44.6% (n = 61 386) reported from countries in the WHO African Region. More than half (56.6%, n = 77 873) were among children <1 year of age, and 4.0% (n = 4010) died among those with reported disease outcome. Among suspected meningitis cases, 8.6% (n = 11 798) were classified as probable bacterial meningitis. One of 3 bacterial pathogens was identified in 30.3% (n = 3576) of these cases, namely S. pneumoniae (n = 2177 [60.9%]), H. influenzae (n = 633 [17.7%]), and N. meningitidis (n = 766 [21.4%]). Among confirmed bacterial meningitis cases with outcome reported, 11.0% died; case fatality ratio varied by pathogen (S. pneumoniae, 12.2%; H. influenzae, 6.1%; N. meningitidis, 11.0%). Among the 277 children who died with confirmed bacterial meningitis, 189 (68.2%) had confirmed S. pneumoniae. The proportion of pneumococcal cases with pneumococcal conjugate vaccine (PCV) serotypes decreased as the number of countries implementing PCV increased, from 77.8% (n = 273) to 47.5% (n = 248). Of 397 H. influenzae specimens serotyped, 49.1% (n = 195) were type b. Predominant N. meningitidis serogroups varied by region.

Conclusions: This multitier, global surveillance network has supported countries in detecting and serotyping the 3 principal invasive bacterial pathogens that cause pediatric meningitis. Streptococcus pneumoniae was the most common bacterial pathogen detected globally despite the growing number of countries that have nationally introduced PCV. The large proportions of deaths due to S. pneumoniae reflect the high proportion of meningitis cases caused by this pathogen. This global network demonstrated a strong correlation between PCV introduction status and reduction in the proportion of pneumococcal meningitis infections caused by vaccine serotypes. Maintaining case-based, active surveillance with laboratory confirmation for prioritized vaccine-preventable diseases remains a critical component of the global agenda in public health.The World Health Organization (WHO)-coordinated Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network reported data from 2014 to 2019, contributing to the estimates of the disease burden and serotypes of pediatric meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.

Keywords: invasive bacterial disease; meningitis; meningococcal; pneumococcal; pneumococcal conjugate vaccine; surveillance; vaccine preventable disease.

Figure 1.

World Health Organization (WHO) Member States and network laboratories that reported surveillance and laboratory data to the WHO Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network, 2019.

Figure 2.

Number of children <5 years old with suspected meningitis who were reported and for whom specimens were collected and laboratory testing completed as part of the World Health Organization (WHO) Global Invasive Bacterial Vaccine-Preventable Disease Surveillance Network, by WHO region, 2014–2019. Across all regions from 2014 to 2019, 137 609 cases were identified from 58 countries, 119 808 specimens (87% of enrolled cases) were collected, and 105 418 specimens (88% of collected specimens) were tested by culture, polymerase chain reaction, and/or rapid diagnostic tests.

Figure 3.

A, Serotype distribution of specimens that tested positive for Streptococcus pneumoniae (Sp) in the World Health Organization (WHO) Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network by WHO region, 2014–2019 (N = 873 specimens serotyped). N in brackets indicate the number of specimens that were serotyped for Sp in each WHO region. The number of countries with specimens serotyped is indicated below each WHO region. Countries include those that had and had not introduced PCV. Serotypes indicated in colors are those that are included in 13-valent pneumococcal conjugate vaccine (PCV13). B, Serotype distribution of specimens that tested positive for Sp in the WHO IB-VPD Surveillance Network by country PCV introduction status, 2014–2019 (N = 873 specimens serotyped). Pre–vaccine introduction includes years when a country had not yet introduced PCV nationally into its routine immunization program and the year of introduction, if applicable. Post–vaccine introduction includes full years when PCV was part of the country’s routine immunization program.

Figure 3.

A, Serotype distribution of specimens that tested positive for Streptococcus pneumoniae (Sp) in the World Health Organization (WHO) Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network by WHO region, 2014–2019 (N = 873 specimens serotyped). N in brackets indicate the number of specimens that were serotyped for Sp in each WHO region. The number of countries with specimens serotyped is indicated below each WHO region. Countries include those that had and had not introduced PCV. Serotypes indicated in colors are those that are included in 13-valent pneumococcal conjugate vaccine (PCV13). B, Serotype distribution of specimens that tested positive for Sp in the WHO IB-VPD Surveillance Network by country PCV introduction status, 2014–2019 (N = 873 specimens serotyped). Pre–vaccine introduction includes years when a country had not yet introduced PCV nationally into its routine immunization program and the year of introduction, if applicable. Post–vaccine introduction includes full years when PCV was part of the country’s routine immunization program.

Figure 4.

Serotype distribution of specimens that tested positive for Streptococcus pneumoniae (Sp) by year, 2014–2019, restricted to countries that introduced the 10- or 13-valent pneumococcal conjugate vaccine (PCV) during or prior to 2019. The proportion of countries included in this analysis that had introduced PCVs during or prior to each year is indicated by the line (and the percentage shown near the line). For example, in 2014, 24 of 31 countries (77.4%) had introduced PCV nationally during or prior to 2014. Among these 31 countries that reported serotype data in 2014, 120 (49.0%) cases had a PCV serotype whereas 125 (51.0%) had a non-PCV serotype. Although 7 countries reported in 2014 had not yet introduced PCV nationally, they were included in this analysis because they introduced the vaccine in the subsequent years (2015–2019). The numbers on the bars indicate the number of specimens with a detected Sp serotype including non-PCV type and PCV type. PCV10 serotypes include the following: 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F; PCV13 includes the serotypes included in PCV10 plus 3, 6A, and 19A. The PCV type and non-PCV type were analyzed based on the PCV type that was introduced nationally by the respective countries during that particular year.