ABSTRACT

Objective:

To analyze the spatiotemporal epidemiological dynamics of meningitis in Brazil, between 2010 and 2019.

Methods:

Descriptive ecological study with cases and deaths due to meningitis in Brazil (2010-2019) in the National Notifiable Diseases Information System (Sistema de Informações de Agravos de Notificação – SINAN). The following analyses were performed: (I) frequency analyses of cases and deaths, prevalence rates, mortality, lethality, Fisher's exact test, and chi-square test; (II) Prais-Winstein regression; and (III) Global, Local Moran's index, and Kernel density.

Results:

182,126 cases of meningitis were reported in Brazil, of which 16,866 (9.26%) resulted in death, with prevalence rates of 9.03/100,000 inhabitants, mortality of 0.84/100,000 inhabitants, and lethality of 9.26%. There was a noted trend of decreasing prevalence rates (−9.5%, 95% confidence interval — 95%CI −13.92; −4.96, p<0.01) and mortality (−11.74%, 95%CI −13.92; −9.48, p<0.01), while lethality remained stable (−2.08%, 95%CI −4.9; 0.8; p<0.1941). The majority of cases were viral meningitis (45.7%), among 1-9 years old (32.2%), while the highest proportion of deaths was due to bacterial meningitis (68%), among 40-59 years old (26.3%). In the Moran and Kernel maps of prevalence and mortality rates, municipalities in the South, Southeast, and the capital of Pernambuco in the Northeast stood out with high rates; as for lethality, the North, Northeast, and Southeast coastal areas were highlighted.

Conclusion:

A decrease in meningitis cases and deaths was found in this study; however, the lethality rate was higher in areas with lower prevalence, emphasizing the need to enhance actions for identifying, monitoring, and providing health care for cases, as well as expanding vaccination coverage.

Keywords:
Meningitis; Vaccine-preventable diseases; Public health; Epidemiologic factors; Time series studies; Spatial analysis

INTRODUCTION

Meningitis is a condition marked by the inflammation of the meninges and the subarachnoid space, which are protective layers surrounding the central nervous system. These layers consist of three membranes — dura mater, arachnoid mater, and pia mater. Within these layers lies the cerebrospinal fluid (CSF), a vital biological fluid that acts as a cushion for the nervous system¹1 Gomes LS, Passos BVS, Azevedo PSS, Silva Júnior FTS, Sampaio LS, Matos LFL, et al. Aspectos epidemiológicos das meningites virais no estado do Piauí no período de 2007 a 2017. Rev Eletrônica Acervo Saúde 2019; 11(10): e433. https://doi.org/10.25248/reas.e433.2019
https://doi.org/10.25248/reas.e433.2019... –³3 Silva HCG, Mezzaroba N. Meningite no Brasil em 2015: o panorama da atualidade. ACM Arq Catarin Med 2018; 47(1): 34-46..

The etiology of meningitis can be linked to various infectious agents, including viruses, bacteria, and other pathogens. However, non-infectious factors such as certain medications and other medical conditions can also trigger this inflammatory process³3 Silva HCG, Mezzaroba N. Meningite no Brasil em 2015: o panorama da atualidade. ACM Arq Catarin Med 2018; 47(1): 34-46.,⁴4 Macedo Junior AM, Nicoletti GP, Santos ECG. Meningite: breve análise sobre o perfil epidemiológico no Brasil-BR, nos anos de 2018 e 2019. Int J Dev Res 2021; 11(1): 43751-6. https://doi.org/10.37118/ijdr.20705.01.2021
https://doi.org/10.37118/ijdr.20705.01.2... .

Viral meningitis is the most common type in the population, as it is caused by a larger variety of pathogens compared to bacterial meningitis. This prevalence is often associated with the socioeconomic vulnerability of the population⁵5 Duque MAA, Silva TC, França ICC, Carvalho SMS, França ICC, Silva GS, et al. Aspectos epidemiológicos, clínicos e laboratoriais da meningite viral: uma revisão de literatura. Braz J Dev 2023, 9(1): 4086-96. https://doi.org/10.34117/bjdv9n1-283
https://doi.org/10.34117/bjdv9n1-283... . However, bacterial meningitis is considered the most severe and potentially lethal form due to its severity compared to the viral type⁵5 Duque MAA, Silva TC, França ICC, Carvalho SMS, França ICC, Silva GS, et al. Aspectos epidemiológicos, clínicos e laboratoriais da meningite viral: uma revisão de literatura. Braz J Dev 2023, 9(1): 4086-96. https://doi.org/10.34117/bjdv9n1-283
https://doi.org/10.34117/bjdv9n1-283... ,⁶6 Dias FCF, Rodrigues Junior CA, Cardoso CRL, Veloso FPFS, Rosa RTAS, Figueiredo BNS. Meningite: aspectos epidemiológicos da doença na região norte do Brasil. Revista de Patologia do Tocantins 2017; 4(2): 46-9. https://doi.org/10.20873/uft.2446-6492.2017v4n2p46
https://doi.org/10.20873/uft.2446-6492.2... .

Meningitis remains a significant public health concern despite being preventable through vaccination. Globally, it is estimated that there are 1.2 million cases of meningitis annually, resulting in approximately 135,000 deaths. Without prompt treatment, its lethality can reach as high as 50%⁷7 GBD 2016 Meningitis Collaborators. Global, regional, and national burden of meningitis, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol 2018, 17(2): 1061-82. https://doi.org/10.1016/S1474-4422(18)30387-9
https://doi.org/10.1016/S1474-4422(18)30... . In Brazil, suspected or confirmed cases of meningitis are subject to immediate mandatory notification, requiring reporting to the State and Municipal Health Secretariats within 24 hours⁸8 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Boletim Epidemiológico 25 [Internet]. 2021 [cited on Jul 17, 2022]. Available at: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/boletins/boletins-epidemiologicos/edicoes/2021/boletim-epidemiologico-25_svs.pdf/view
https://www.gov.br/saude/pt-br/centrais-... .

Reports of meningitis cases in Brazil exhibit regional disparities, with a higher concentration observed in the South, Southeast, and Northeast regions. This pattern is evident in studies focusing on bacterial meningitis cases as well as those analyzing all types of the disease⁹9 Silva AFT, Valente FS, Sousa LD, Cardoso PNM, Silva MA, Santos DR. Estudo epidemiológico sobre meningite bacteriana no Brasil no período entre 2009 a 2018. Rev Med 2021; 100(3): 220-8. https://doi.org/10.11606/issn.1679-9836.v100i3p220-228
https://doi.org/10.11606/issn.1679-9836.... ,¹⁰10 Moraes GFQ, Galdino MAO, Teixeira APC. Impacto da meningite entre os anos de 2010 e 2020 no Brasil: um estudo documental. Rev Ciênc Méd Biol 2022 21(3): 505-13. https://doi.org/10.9771/cmbio.v21i3.46627
https://doi.org/10.9771/cmbio.v21i3.4662... .

Hence, in 2021, the World Health Organization (WHO) initiated a global roadmap with the goal of managing meningitis and decreasing fatalities from the illness by 2030. This initiative seeks to eradicate outbreaks of bacterial meningitis, decrease instances of vaccine-preventable bacterial meningitis, and enhance the quality of life for those impacted by the disease¹¹11 World Health Organization. Defeating meningitis by 2030: a global road map [Internet]. Genebra: WHO, 2021 [cited on Jul 07, 2022]. Available at: https://www.who.int/initiatives/defeating-meningitis-by-2030
https://www.who.int/initiatives/defeatin... .

Presently, vaccines stand as one of the primary methods to prevent meningitis. In Brazil, these vaccines are integrated into the national immunization schedule of the National Immunization Program (Programa Nacional de Imunização – PNI) and are provided free of charge through the Brazilian Unified Health System (Sistema Único de Saúde – SUS). Included among these vaccines are the 10-valent pneumococcal (PCV 10), meningococcal C (Conjugated), 23-valent pneumococcal (PPV 23), pentavalent and meningococcal ACWY (Conjugated). Studies demonstrate that vaccination has yielded a beneficial impact in reducing both cases and fatalities from the disease in recent years¹³13 Neves RC, Böhm AW, Costa CS, Flores TR, Soares ALG, Wehrmeister FC. Cobertura da vacina meningocócica C nos estados e regiões do Brasil em 2012. Rev Bras Med Fam Comunidade 2016; 11(38): 1-10. https://doi.org/10.5712/rbmfc11(38)1122
https://doi.org/10.5712/rbmfc11(38)1122... .

Clinical manifestations of meningitis vary based on factors such as age, duration of illness, and causative agent. Key signs and symptoms include fever, hypothermia, diarrhea, lethargy, neck stiffness (meningeal irritation), lower back pain, photophobia, dyspnea, and the emergence of petechiae and maculopapular rashes¹⁴14 Teixeira AB, Cavalcante JCV, Moreno IC, Soares IA, Holanda FOA. Meningite bacteriana: uma atualização. Rev Bras Anal Clin 2018; 50(4): 327-329. https://doi.org/10.21877/2448-3877.201800725
https://doi.org/10.21877/2448-3877.20180... . Laboratory confirmation can be achieved through polymerase chain reaction (PCR) tests, latex agglutination, and culture, with the latter considered the gold standard for diagnosing bacterial meningitis⁸8 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Boletim Epidemiológico 25 [Internet]. 2021 [cited on Jul 17, 2022]. Available at: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/boletins/boletins-epidemiologicos/edicoes/2021/boletim-epidemiologico-25_svs.pdf/view
https://www.gov.br/saude/pt-br/centrais-... .

Given this context, conducting this research is justified due to the significance of understanding the epidemiological dynamics of meningitis in Brazil and contributing to the spatial and temporal comprehension of the disease and its features. Employing geographic, socioeconomic, and health data enables the characterization of epidemiological scenarios relevant to public and collective health¹⁵15 Oliveira DS, Chiaravalloti Neto F, Mota TS, Araujo DB, Sartori AMC. Spatial analysis of pneumococcal meningitis in São Paulo in the pre-and post-immunization era. Rev Saúde Pública 2019; 53: 59. https://doi.org/10.11606/S1518-8787.2019053001183
https://doi.org/10.11606/S1518-8787.2019... ,¹⁶16 Cavalcante JR, Abreu AJL. COVID-19 no município do Rio de Janeiro: análise espacial da ocorrência dos primeiros casos e óbitos confirmados. Epidemiol Serv Saúde 2020; 29(3): e2020204. https://doi.org/10.5123/S1679-49742020000300007
https://doi.org/10.5123/S1679-4974202000... .

The present study aimed to address the following question: given the status of meningitis as a public health concern, what is the epidemiological landscape of meningitis in Brazil in recent years? Thus, the objective was to analyze the spatiotemporal epidemiological dynamics of meningitis in Brazil between 2010 and 2019.

METHODS

A descriptive and ecological study was conducted, employing a spatiotemporal approach, to analyze cases and deaths attributed to various types of meningitis (bacterial, viral, and caused by other agents), in Brazil, from 2010 to 2019. The study utilized data sourced from the National Notifiable Diseases Information System (Sistema de Informação de Agravos de Notificação – SINAN), which was established in 1993 and has undergone continuous enhancements. SINAN is responsible for reporting diseases listed in the National Compulsory Disease Notification List¹⁷17 Rocha MS, Bartholomay P, Cavalcante MV, Medeiros FC, Codenotti SB, Pelissari DM, et al. Notifiable Diseases Information System (SINAN): main features of tuberculosis-relatid notification and data analysis. Epidemiol Serv Saude 2020; 29(1): e2019017. https://doi.org/10.5123/S1679-49742020000100009
https://doi.org/10.5123/S1679-4974202000... .

Data collection was conducted using the TabNet platform of the SUS IT Department (DataSUS), specifically under the "Epidemiological and Morbidity" tab. The option "Notifiable Diseases and Diseases — 2007 onwards (SINAN)" was selected, followed by "Meningitis." Subsequently, the data tabulation process was initiated¹⁸18 Brasil. Ministério da Saúde. Departamento de Informática do Sistema Único de Saúde (DataSUS). TabNet [Internet] 2021 [cited on Jan 30, 2021]. Available at: https://datasus.saude.gov.br/informacoes-de-saude-tabnet/
https://datasus.saude.gov.br/informacoes... . Population data were obtained from population estimates provided by the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística – IBGE)¹⁹19 Brasil. Instituto Brasileiro de Geografia e Estatística. Panorama Brasil. IBGE Cidades [Internet]. 2022 [cited on Jul 07, 2022]. Available at: https://cidades.ibge.gov.br/brasil/panorama
https://cidades.ibge.gov.br/brasil/panor... .

As meningitis is a notifiable disease, cases must be reported within 24 hours to the Municipal and State Health Secretariats by healthcare professionals or individuals responsible for public and private health services providing patient care. Additionally, any citizen can report a suspected case. Notification is carried out using the "Meningitis Investigation Form" and registered on Sinan²⁰20 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Departamento de Articulação Estratégica de Vigilância em Saúde. Guia de vigilância em saúde [Internet]. 5a ed. Brasília: Ministério da Saúde; 2022. Available at: https://bvsms.saude.gov.br/bvs/publicacoes/guia_vigilancia_saude_5ed_rev_atual.pdf
https://bvsms.saude.gov.br/bvs/publicaco... .

Therefore, the study area encompassed Brazil, a country located in South America, with a territorial extension of 8,510,345.538 km² and an estimated population of 210,147,125 inhabitants for the year 2019. Brazil is administratively divided into 5,570 municipalities, 27states, and five geographic regions (North, Northeast, Southeast, South, and Central-West)¹⁹19 Brasil. Instituto Brasileiro de Geografia e Estatística. Panorama Brasil. IBGE Cidades [Internet]. 2022 [cited on Jul 07, 2022]. Available at: https://cidades.ibge.gov.br/brasil/panorama
https://cidades.ibge.gov.br/brasil/panor... .

To characterize the general epidemiological scenario of meningitis in Brazil, absolute and relative frequencies of the selected variables were calculated. These variables include gender, age range, race/color, confirmation criteria, etiology, type of meningitis (grouped by the authors based on etiology), case evolution, pregnant woman status, year of symptom onset, geographic region of residence, state of residence, and municipality of residence¹⁸18 Brasil. Ministério da Saúde. Departamento de Informática do Sistema Único de Saúde (DataSUS). TabNet [Internet] 2021 [cited on Jan 30, 2021]. Available at: https://datasus.saude.gov.br/informacoes-de-saude-tabnet/
https://datasus.saude.gov.br/informacoes... (the categories of these variables are included in the supplementary file). Additionally, prevalence rates (per 100,000 inhabitants), mortality coefficients (per 100,000 inhabitants), and lethality rates (per 100%) were computed.

To calculate the prevalence rate and mortality coefficient, the population projection of the respective year was used as the denominator. The total rates were calculated using the sum of the population projections for the ten years analyzed as the denominator.

Fisher's exact test and the chi-square test were utilized to determine whether there are differences between the averages of cases and deaths, with a significance level of 5% (p<0.05). The analyses were conducted using Microsoft Office software Excel 2016^® and R version 4.2.0.

To analyze the temporal evolution, the Prais-Winsten generalized linear regression method was employed. In this method, the prevalence, mortality, and lethality rates of meningitis were considered as dependent variables (Y), while the years studied were treated as the independent variable (X), with a 95% confidence interval. This approach allows inference regarding whether the temporal trend is increasing (positive), decreasing (negative), or stationary (when there is no significant difference between the obtained value and zero). For this analysis, R version 4.2.0 was used, along with the prais package²¹21 Antunes JLF, Cardoso MRA. Uso da análise de séries temporais em estudos epidemiológicos. Epidemiol Serv Saúde 2015; 24(3): 565-76. https://doi.org/10.5123/S1679-49742015000300024
https://doi.org/10.5123/S1679-4974201500... ,²²22 Cunha AP, Cruz MM, Torres RMC. Tendência da mortalidade por aids segundo características sociodemográficas no Rio Grande do Sul e em Porto Alegre: 2000-2011. Epidemiol Serv Saúde 2016; 25(3): 477-86. https://doi.org/10.5123/S1679-49742016000300004
https://doi.org/10.5123/S1679-4974201600... .

In the spatial analysis, global and local Moran indices and Kernel density were calculated. The global Moran index was utilized to ascertain the presence of spatial autocorrelation in the distribution of meningitis prevalence, mortality, and lethality rates. This method is predicated on the null hypothesis (H₀), which posits that spatial factors do not influence the distribution of the disease, event, or condition. Additionally, values obtained in this analysis range between −1 and 1, with values closer to 1 indicating a stronger presence of spatial autocorrelation, while values close to zero suggest that H₀ is true²³23 Nahas AK. Padrões espaço-temporais da taxa de mortalidade fetal no estado de São Paulo, Brasil, 2005-2016 [tese de doutorado]. São Paulo: Faculdade de Saúde Pública da Universidade de São Paulo (USP); 2018.,²⁴24 Silva LR, Arruda LES, Silva AC, Teixeira CMB, Lira G, Ferreira RJ, et al. Negligência e desafios na saúde coletiva: Análise epidemiológica dos casos de doença de Chagas aguda no Brasil, no período de 2009 a 2018. Braz J Dev 2020; 6(8): 61734-52. https://doi.org/10.34117/bjdv6n8-555
https://doi.org/10.34117/bjdv6n8-555... . To validate the findings, a random permutation test with 9,999 permutations and a 95% confidence interval was conducted²⁴24 Silva LR, Arruda LES, Silva AC, Teixeira CMB, Lira G, Ferreira RJ, et al. Negligência e desafios na saúde coletiva: Análise epidemiológica dos casos de doença de Chagas aguda no Brasil, no período de 2009 a 2018. Braz J Dev 2020; 6(8): 61734-52. https://doi.org/10.34117/bjdv6n8-555
https://doi.org/10.34117/bjdv6n8-555... .

The local Moran index enables the visualization of clusters of municipalities with similar behavior patterns, based on the statistical significance criterion²⁴24 Silva LR, Arruda LES, Silva AC, Teixeira CMB, Lira G, Ferreira RJ, et al. Negligência e desafios na saúde coletiva: Análise epidemiológica dos casos de doença de Chagas aguda no Brasil, no período de 2009 a 2018. Braz J Dev 2020; 6(8): 61734-52. https://doi.org/10.34117/bjdv6n8-555
https://doi.org/10.34117/bjdv6n8-555... . Meanwhile, the Kernel density tool was employed to pinpoint areas of rate concentration in geographic space. This method utilizes statistical analysis by interpolating point data per unit area to estimate density curves and convert them into data on a continuous surface²⁵25 Silverman BW. Density estimation for statistics and data analysis. Londres: Chapman and Hall; 1986..

The current study did not require approval from the Research Ethics Committee, as it exclusively utilized secondary data available in the public domain. According to Resolution no. 510/16 of the National Health Council (Conselho Nacional de Saúde – CNS), research of this nature is exempt from the requirement for CEP approval²⁶26 Brasil. Ministério da Saúde. Conselho Nacional de Saúde. Resolução n° 510, de 7 de abril de 2016 [Internet]. 2016 [cited on Oct 20, 2021]. Available at: https://conselho.saude.gov.br/resolucoes/2016/Reso510.pdf
https://conselho.saude.gov.br/resolucoes... .

RESULTS

Between 2010 and 2019, a total of 182,126 cases of meningitis were reported in Brazil. Among these cases, 16,866 (9.26%) resulted in death. The average prevalence rate during this period was 9.03 cases per 100,000 inhabitants, with an average mortality coefficient of 0.84 deaths per 100,000 inhabitants. The average lethality rate was 9.26%.

Regarding the epidemiological characterization of the cases, it was observed that the majority occurred in male individuals (59.12%). The highest proportion was in the age group from one to nine years (32.18%), and the majority were of white race/color (45.17%). The largest portion of cases had viral etiology (45.69%), confirmed through chemocytological examination (60.99%). Additionally, 79.37% of cases progressed to cure (Table 1).

Regarding deaths (n=16,866), the majority occurred in males (58.73%), with the highest proportion in the age range of 40 to 59 years (26.34%). Most of the deceased were of white race/color (39.16%). The main cause of these deaths was bacterial meningitis (22.15%), and the most commonly used confirmation method was culture (29.15%) (Table 1).

In the temporal trend analysis, a decrease in the annual percentage variation in the prevalence rate of −9.5% (95% CI −13.92; −4.96, p<0.01) was observed over the period studied. Similarly, the mortality rate showed a significant decrease of −11.74% (95% CI −13.92; −9.48, p<0.01). Although the lethality rate demonstrated a stationary trend, there was a decrease of −2.08% (95% CI −4.9; 0.8; p<0.1941) over the study period (Figure 1).

Furthermore, when observing the stratification by type of meningitis (Table 2), a stationary trend in the prevalence of viral meningitis and a decreasing trend in bacterial meningitis and other etiological agents were noted. For mortality, a stationary trend was also observed for viral meningitis, whereas a decreasing trend was observed for bacterial meningitis and other types. Regarding lethality, all types of meningitis showed a stationary trend.

Regarding the analysis of the prevalence of meningitis, according to geographic region, it was observed that the South Region had a rate of 12.48 cases per 100 thousand inhabitants, followed by the Southeast Region (11.65 cases per 100 thousand inhabitants), Northeast Region (5.59 cases per 100 thousand inhabitants), Central-West Region (5.54 cases per 100 thousand inhabitants), and North Region (4.54 cases per 100 thousand inhabitants).

For the mortality coefficient, the Southeast Region stood out with a rate of 1.08 deaths per 100 thousand inhabitants, followed by the South Region (0.89 deaths per 100 thousand inhabitants), Central-West Region (0.67 deaths per 100 thousand inhabitants), North Region (0.65 deaths per 100 thousand inhabitants), and Northeast Region (0.54 deaths per 100 thousand inhabitants). In terms of lethality, the North Region had the highest rate at 14.21%, followed by the Central-West Region (12.08%), Northeast Region (9.73%), Southeast Region (9.25%), and South Region (7.15%).

The presence of spatial autocorrelation in the distribution of the meningitis prevalence rate was confirmed by the Global Moran index (I=0.54; p-value=0; z-score=13.80). In the local Moran analysis, municipalities in the states of São Paulo, Minas Gerais, Rio de Janeiro, Espírito Santo, Mato Grosso do Sul, Paraná, Santa Catarina, Rio Grande do Sul, and Pernambuco stood out, showing clusters of municipalities with high rates surrounded by neighboring municipalities with similarly high rates (Figure 2A).

Regarding the mortality coefficient, weak spatial autocorrelation was identified (I=0.03; p-value=0.34; z-score=0.93). According to the local Moran map, similar patterns were observed compared to the prevalence rate map, with municipalities in the states of São Paulo, Minas Gerais, Rio de Janeiro, Espírito Santo, Mato Grosso do Sul, Paraná, and Santa Catarina standing out (Figure 2B).

In the lethality map, the presence of fragile spatial autocorrelation was also confirmed (I=0.03; p-value=0; z-score=23.57). However, a change in the highlighted areas of the map was observed. Some areas that did not stand out in the previously described maps emerged in the lethality map, such as municipalities in the states of Amazonas, Pará, Maranhão, Bahia, Minas Gerais, Rio de Janeiro, and Espírito Santo (Figure 2C).

Kernel density analysis of the prevalence rate revealed that certain municipalities in the states of São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul exhibit high and medium density areas (Figure 3A). These areas were also common to the mortality coefficient map, showing high and medium concentrations of deaths, along with the states of Pernambuco, Minas Gerais, and Rio de Janeiro (Figure 3B). Concerning lethality, the highest density areas stood out in the states of Minas Gerais and Paraíba, while municipalities in the states of São Paulo, Minas Gerais, Paraná, Santa Catarina, Rio Grande do Sul, Maranhão, and some municipalities along the northeastern coast exhibited areas of medium concentration (Figure 3C).

DISCUSSION

Based on the analyses conducted in this study, it was observed that there is a trend toward a decrease in the prevalence and mortality rates of meningitis in Brazil. However, lethality rates remain stationary, posing a challenge for health authorities. Additionally, there was a higher prevalence of cases attributed to viral meningitis, while bacterial meningitis accounted for greater mortality. Moreover, a greater concentration of cases was found in the states of the South and Southeast Regions.

As supported by the scientific literature, the study also identified a higher concentration of meningitis cases among children. This observation may be associated with factors such as the development of the immune system, incomplete vaccination schedules, and the close proximity of children in educational settings, which can facilitate the transmission of infectious agent(s)³3 Silva HCG, Mezzaroba N. Meningite no Brasil em 2015: o panorama da atualidade. ACM Arq Catarin Med 2018; 47(1): 34-46.,⁶6 Dias FCF, Rodrigues Junior CA, Cardoso CRL, Veloso FPFS, Rosa RTAS, Figueiredo BNS. Meningite: aspectos epidemiológicos da doença na região norte do Brasil. Revista de Patologia do Tocantins 2017; 4(2): 46-9. https://doi.org/10.20873/uft.2446-6492.2017v4n2p46
https://doi.org/10.20873/uft.2446-6492.2... .

In relation to the criterion of race/skin color, existing literature indicates a predominance of cases among individuals of white ethnicity, consistent with the findings of this study. However, it is important to acknowledge that this observation may vary across different studies due to factors such as the demographic composition of specific regions, the ethnic diversity of the Brazilian population, and issues related to data reporting. It is noteworthy that a considerable proportion of cases (more than 20%) and deaths (16%) had this field left blank in the Sinan notification records, which may introduce some uncertainty into the analysis⁸8 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Boletim Epidemiológico 25 [Internet]. 2021 [cited on Jul 17, 2022]. Available at: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/boletins/boletins-epidemiologicos/edicoes/2021/boletim-epidemiologico-25_svs.pdf/view
https://www.gov.br/saude/pt-br/centrais-... ,²⁷27 Matos AC, Fecury AA, Oliveira E, Dendasck CV, Dias CAGM. Número de casos confirmados de meningite no Brasil no período de 2011 a 2015. Revista Científica Multidisciplinar Núcleo do Conhecimento 2020; 5(1): 121-30. https://doi.org/10.32749/nucleodoconhecimento.com.br/saude/meningite-no-brasil
https://doi.org/10.32749/nucleodoconheci... .

The research also identified that the majority of recurrent meningitis cases in the population are viral in nature, potentially attributed to the virus's ability to spread easily in the environment. Existing literature supports this observation, noting that viral meningitis is more prevalent and typically presents with milder symptoms. However, bacterial meningitis remains a significant concern due to its considerable morbidity and mortality rates, particularly among children in regions characterized by higher economic and social vulnerability²2 van de Beek D, Brouwer M, Hasbun R, Koedel U, Whitney CG, Wijdicks E. Community-acquired bacterial meningitis. Nat Rev Dis Primers 2016; 2: 16074. https://doi.org/10.1038/nrdp.2016.74
https://doi.org/10.1038/nrdp.2016.74... ,³3 Silva HCG, Mezzaroba N. Meningite no Brasil em 2015: o panorama da atualidade. ACM Arq Catarin Med 2018; 47(1): 34-46.,²³23 Nahas AK. Padrões espaço-temporais da taxa de mortalidade fetal no estado de São Paulo, Brasil, 2005-2016 [tese de doutorado]. São Paulo: Faculdade de Saúde Pública da Universidade de São Paulo (USP); 2018.,²⁸28 Aguiar TS, Fonseca MC, Santos MC, Nicoletti GP, Alcoforado DSG, Santos SCD, et al. Perfil epidemiológico da meningite no Brasil, com base nos dados provenientes do DataSUS nos anos de 2020 e 2021. Res Soc Dev 2022; 11(3): e50811327016. http://dx.doi.org/10.33448/rsd-v11i3.27016
http://dx.doi.org/10.33448/rsd-v11i3.270... .

Advancements in diagnostic techniques and the continuous training of healthcare professionals are essential strategies for the prompt detection of meningitis cases in the population. Early detection enables timely initiation of treatment, increasing the likelihood of a complete recovery without long-term complications and reducing mortality rates associated with the disease²⁷27 Matos AC, Fecury AA, Oliveira E, Dendasck CV, Dias CAGM. Número de casos confirmados de meningite no Brasil no período de 2011 a 2015. Revista Científica Multidisciplinar Núcleo do Conhecimento 2020; 5(1): 121-30. https://doi.org/10.32749/nucleodoconhecimento.com.br/saude/meningite-no-brasil
https://doi.org/10.32749/nucleodoconheci... ,²⁹29 Teixeira DC, Diniz LMO, Guimarães NS, Moreira HMAS, Teixeira CC, Romanelli RMC. Fatores de risco associados aos desfechos da meningite bacteriana pediátrica: uma revisão sistemática. J Pediatr (Rio J) 2020; 96(2): 159-67. https://doi.org/10.1016/j.jped.2019.07.003
https://doi.org/10.1016/j.jped.2019.07.0... .

According to the epidemiological bulletin from the Ministry of Health⁸8 Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Boletim Epidemiológico 25 [Internet]. 2021 [cited on Jul 17, 2022]. Available at: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/boletins/boletins-epidemiologicos/edicoes/2021/boletim-epidemiologico-25_svs.pdf/view
https://www.gov.br/saude/pt-br/centrais-... , there has been a notable decline in the incidence of pneumococcal meningitis cases in Brazil since the introduction of PCV-10 vaccination in 2010. The incidence dropped from 2.5 cases per 100 thousand inhabitants in 2007 to 1 case per 100 thousand inhabitants in 2015, with rates remaining relatively stable in subsequent years. This underscores the significance of population vaccination as the primary strategy for mitigating and controlling meningitis cases across Brazil.

The spatial analysis revealed a clustering of meningitis cases and deaths in states located in the South (Paraná, Santa Catarina, and Rio Grande do Sul), Southeast (São Paulo, Minas Gerais, Rio de Janeiro, Espírito Santo), and Central-West (Mato Grosso do Sul) regions. This concentration could be attributed to several factors, including the advancement of health surveillance methods in these regions for early case detection and/or higher population density, particularly notable in the Southeast. These conditions may facilitate the transmission of infectious agents within the population³3 Silva HCG, Mezzaroba N. Meningite no Brasil em 2015: o panorama da atualidade. ACM Arq Catarin Med 2018; 47(1): 34-46.,²⁷27 Matos AC, Fecury AA, Oliveira E, Dendasck CV, Dias CAGM. Número de casos confirmados de meningite no Brasil no período de 2011 a 2015. Revista Científica Multidisciplinar Núcleo do Conhecimento 2020; 5(1): 121-30. https://doi.org/10.32749/nucleodoconhecimento.com.br/saude/meningite-no-brasil
https://doi.org/10.32749/nucleodoconheci... ,³⁰30 Rodrigues EMB, Milagres BS. Meningite: perfil epidemiológico da doença no brasil nos anos de 2007 a 2013 [Trabalho de conclusão de curso]. Brasília: Faculdade de ciências da educação e saúde do Centro Universitário de Brasília (UniCEUB); 2015..

The contrast between the lethality map and the prevalence/mortality maps is noteworthy. Areas with lower prevalence or mortality rates, particularly in the North and Northeast Regions, exhibited higher lethality rates. This observation might be linked to challenges within the health system to promptly identify cases, thus preventing adverse outcomes such as death. Additionally, factors such as low vaccination coverage and socioeconomic and regional disparities could contribute to these higher lethality rates. These regions are historically marked by socioeconomic inequality and health disparities, which may exacerbate the impact of meningitis¹³13 Neves RC, Böhm AW, Costa CS, Flores TR, Soares ALG, Wehrmeister FC. Cobertura da vacina meningocócica C nos estados e regiões do Brasil em 2012. Rev Bras Med Fam Comunidade 2016; 11(38): 1-10. https://doi.org/10.5712/rbmfc11(38)1122
https://doi.org/10.5712/rbmfc11(38)1122... ,³¹31 Barata RB, Pereira SM. Desigualdades sociais e cobertura vacinal na cidade de Salvador, Bahia. Rev Bras Epidemiol 2013; 16(2): 266-77. https://doi.org/10.1590/S1415-790X2013000200004
https://doi.org/10.1590/S1415-790X201300... .

The study's limitations include the potential for biases inherent in the notification and updating of cases and deaths on Sinan, which may not accurately reflect the epidemiological landscape of meningitis in Brazil. Additionally, the presence of fields not filled in or ignored in a percentage of notifications poses challenges in understanding the true extent of meningitis in the country.

To mitigate these limitations, inconsistencies and incompleteness in the database were rigorously analyzed using methodological procedures, with support from the existing scientific literature on the subject. This approach aimed to ensure a robust interpretation of the findings.

In summary, there was a trend toward a decline in both the prevalence and mortality rates of meningitis. However, the persistent lethality rates warrant careful attention, especially in regions where lower prevalence rates coincide with higher lethality rates. This concern arises from the fact that lethality reflects the percentage of individuals who succumb to meningitis after falling ill.

Therefore, it is crucial to intensify efforts to enhance public health services and interventions across the country to promptly detect cases of meningitis, thereby mitigating mortality rates associated with the disease. Moreover, expanding vaccination coverage against vaccine-preventable diseases among the population is imperative. Finally, it is recommended to conduct further research on the epidemiology of meningitis in Brazil, focusing on assessing the impact of vaccination on meningitis cases and deaths, as well as comparing the epidemiological dynamics of different types of meningitis.

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