Towards an African Region free of meningitis epidemics by 2030: vision, progress, challenges and future directions

¹World Health Organization, Regional Office for Africa, Brazzaville, Republic of Congo, ²World Health Organization, World Customs Organization, Abuja, Nigeria, ³World Health Organization, Headquarters, Geneva, Switzerland, ⁴World Health organization, Regional Office for the Eastern Mediterranean, Cairo, Egypt, ⁵Direction de la Lutte contre la Maladie, la Vaccination et la Surveillance Epidemiologique au Ministère de la Santé Publique et de la Prévention, Niamey, Tchad

^&Corresponding author
André Arsène Bita Fouda, World Health Organization, Regional Office for Africa, Brazzaville, Republic of Congo

Introduction    

Acute bacterial meningitis is one of the deadliest and disabling forms of the disease 1 in 6 people die from, death can occur in < 24 hours and 1 in 5 people who survive live with long-term disability. It can cause large and devastating epidemics [1-3]. The infection can be caused by bacteria (Neisseria meningitidis, N. meningitidis), Streptococcus pneumoniae ( S. pneumoniae), Haemophilus influenzae (Hi), and Streptococcus agalactiae or group B streptococcus (GBS), viruses, fungi, and parasites [1]. Meningitis is a major global public health problem with approximately 2.5 million new cases each year, including 1.6 million cases and 240,000 deaths due to bacterial meningitis worldwide, at all ages [1,4,5]. The burden is greatest for babies and young children; Mortality rates vary, with the heaviest burden in sub-Saharan Africa [1-14]. Before 2010, Neisseria meningitidis (N. meningitidis) serogroup A was the leading cause of meningitis in the African meningitis belt, accounting for 80-85% of epidemics [13,14].

The introduction of the meningococcal A conjugate vaccine (MenACV/MenAfriVac) in the African meningitis belt from 2010 resulted in a dramatic reduction in the incidence of N. meningitidis serogroup A [10]. The predominant pathogens causing epidemics in the African meningitis belt are N. meningitidis serogroups C, W and X, and S. pneumoniae [10,15-48]. Although the detection and laboratory confirmation of pathogens causing meningitis epidemics is challenging in these countries, reactive vaccination is vital for controlling them [15-24]. Efforts to eliminate meningitis epidemics resulted in the endorsement of the regional framework to defeat meningitis in the African region by 2030, which envisions making the AFR free of meningitis by 2030 [28-30]. The objective of the study was to describe the epidemiological situation of meningitis disease and assess the impact of control measures implemented from 2010 to 2024 and present future directions to defeat meningitis by 2030 in Africa.

Methods     

A cross-sectional study and literature review were conducted from 2010 to 2024. The quantitative and independent variables used were number of suspected meningitis cases, deaths, case fatality rates (CFR) measuring the severity of disease by defining the total number of deaths as a proportion of reported cases at a specific time, epidemics when a health district crossed epidemic threshold (10 suspected cases/100 000 inhabitants/week) and at least 10 cerebrospinal fluid confirmed, proportion of pathogens causing bacterial meningitis, and immunization coverage rate (percentage of a population that has been appropriately vaccinated against a specific disease) of meningococcal vaccines were collected [40]. Data were collected from countries, specifically from the datasets, registers in health facilities, health districts, notification and investigation sheets, the country databases of the World Health Organization (WHO) African region (AFRO) and of the 47 countries (member states) of AFRO, including the 26 countries of the meningitis belt.

Concerning the global and regional levels, data have been collated from WHO global data, Institute for Health Metrics and Evaluation (IHME) Global Burden of Disease (GBD) dataset, MenAfriNet dataset, the Emergency Dakar Hub meningitis dataset and dashboard, Integrated Disease Surveillance and Response (IDSR) database, Immunization, Vaccines and Biologicals (IVB) dataset on MenACV rollout, and meningitis control dataset. Moreover, data have also been collected from the literature review on meningitis disease especially epidemiology, laboratory confirmation, molecular surveillance, epidemic response, case management and health politics. To ensure effective and systematic implementation of the regional framework to defeat meningitis by 2030, WHO developed a tool for a landscape risk analysis, which helped to rank the 47 countries of the WHO African region according to high, medium, and low priorities. The criteria used to conduct the meningitis high-level landscape analysis in 2021 were meningitis burden, health service assessment and climatic and environmental risk factors.

Concerning burden of meningitis, countries were ranked according to quantitative data and estimates on cases, incidence rates, deaths, mortality rates, and epidemic risk. Data were collated on numbers and rates per 100,000 populations from bacterial meningitis by country from 2017 to 2019, including cases, deaths and epidemics from all meningitis (as the cause is not always identified), and specifically from N. meningitidis, S. pneumoniae, Hi, and GBS if available. Data from global estimates from IHME and GHE were used alongside national surveillance data from AFRO meningitis bulletin and IDSR database. About health service assessment, countries were grouped (independently of burden) by strength of health services relating to meningitis and its sequelae, including vaccination coverage, surveillance, diagnosis, treatment, and care. A combination of quantitative and qualitative measures was used to assess country health services. Indicators for this assessment include introduction of recommended meningitis vaccination programmes for Hib, S. pneumoniae and N. meningitidis, GBS and vaccination coverage rate for Hib, PCV and meningococcal vaccines in groups targeted for vaccination. Availability of national indicators on quality of surveillance and on services for diagnosis (laboratory capacity) and treatment of cases and of sequelae, community care of disability, access and equity are more limited. Possibilities include coverage of essential health services, skilled health worker density and sociodemographic index.

Risk factors predicted meningitis risk from climate and environmental factors were used especially air temperature, relative humidity and surface dust concentration. Meningitis burden, health service assessment and climatic and environmental risk factors were summed in and Excel sheet. Countries were arbitrarily categorized into three ranks based on summed total. Countries that obtained a score between 70 and 100 were classified as high priority for regional implementation framework key interventions, whereas those between 40 and 69 were classified as medium priority, and those below 40 were classified as lower priority.

Results     

Meningitis epidemiological trend of the African meningitis belt

Figure 1 shows that before 2010, the number of suspected meningitis cases and CFR were high compared to the period 2010 to 2024. The number of suspected meningitis cases decreased from 30,103 in 2010 to 26,298 in 2024, whereas deaths decreased from 3,237 in 2010 to 1,377 in 2024. The CFR decreased from 10.8% in 2010 to 5.2% in 2024. A total of 371,564 suspected meningitis cases with 26,119 deaths (case fatality rate (CFR) of 7.0% were reported in the African meningitis belt. From 2011 to 2024, twelve (12) countries of the African meningitis belt experienced bacterial meningitis epidemics, namely, Benin (BEN), Burkina Faso (BFA), Cameroun (CMR), Chad, Côte d´Ivoire (CIV), Democratic Republic of Congo (DRC), Ethiopia, Ghana, Guinea, Niger, Nigeria, and Togo. The pathogens that caused bacterial epidemics were N. meningitidis serogroups C and W and S. pneumoniae. The predominant strains reported during these epidemics were N. meningitidisA ST-5 cc, N. meningitidis C ST-10217 cc, ST103, ST175, N. meningitidisX ST-181 cc, and N. meningitidis W ST C11 cc, S. pneumoniae serotypes 1,5. During meningitis outbreaks, reactive vaccination mass campaigns with MenACV, vaccines containing polysaccharide AC, ACW, and ACYW conjugate, polysaccharide conjugate ACYW, and the meningococcal multivalent conjugate ACWXY (Men5CV) were administered, which contributed to stop epidemics. Concerning pneumococcal meningitis outbreaks, a reactive vaccination campaign was not conducted with PCV because the WHO did not recommend it because of no evidence of its effectiveness.

Bacterial meningitis pathogen profile in the African meningitis belt

Figure 2 shows the disappearance of N. meningitidis A from 2017 and the predominance of the following bacterial meningitis: N. meningitidis C, S. pneumoniae, N. meningitidis W, N. meningitidis X, GBS, Hib, and N. meningitidis. In 2024, 18 countries shared their laboratory data, and the proportion of pathogens was N. meningitidis C (38.5%), S. pneumoniae (26.8%), N. meningitidis C (22.3%), other pathogens (4.3%), Hi non-b (3.9%), Hib (2.3%), N. meningitidis X (1.4%), and indeterminate N. meningitidis (0.4%).

The MenACV rollout from 2010 to 2024

From 2010 to 2024, MenACV had been rolled out in 23 of the 26 countries in the African meningitis belt that are Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Côte d´Ivoire, Democratic Republic of Congo, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Mali, Mauritania, Niger, Nigeria, Senegal, South Sudan, Togo and Uganda. Burkina Faso introduced MenACV in 2010 and Niger started rollout during the same year. Over 350 million persons at highest risk aged between 1 and 29 years, have been vaccinated since December 2010. Additionally, MenAfriVac® was introduced into routine immunization programmes in 14 countries in the African meningitis belt and almost 50 million children aged 1 to 15 yearswere vaccinated as of 2024. These countries include Benin, Burkina Faso, Central African Republic, Chad, Côte d´Ivoire, Eritrea, Gambia, Ghana, Guinea, Guinea Bissau, Mali, Niger, Nigeria, and Togo. In addition, 12 countries conducted catch-up vaccinations for birth cohorts born after the initial rollout. These countries are Benin, Burkina Faso, Chad, Côte d´Ivoire, Gambia, Ghana, Guinea, Guinea-Bissau, Mali, Niger, Nigeria, and Togo. Tanzania and Rwanda in the Africa meningitis belt have chosen to strengthen meningitis enhanced surveillance (Figure 3).

Implementation of national plans to defeat meningitis by 2030 in the African region

Efforts to overcome meningitis led to the endorsement of the regional framework to implement the global road map to defeat meningitis by 2030 by Member States in August 2021 during the Regional Committee 71. Indeed, this regional framework envisions an African Region free of Meningitis by 2030. Moreover, the landscape risk analysis was conducted from September to October 2021 to 38 priority countries identified to implement key activities. Furthermore, the Regional Director officially launched the Regional Framework on September 8, 2022. Two workshops then followed in 2022 and 2023 to support 30 countries of the African region to develop their plans to defeat meningitis. As of 2024, ten (10) countries (Burkina Faso, Cameroon, Central African Republic, Côte d´Ivoire, Guinea, Mali, Niger, Nigeria, and Togo) completed the process of planning and validation, seven countries (Ethiopia, Gambia, Kenya, Liberia, Sierra Leone, Uganda, and Tanzania) are yet to finalize their plans. The other 13 are struggling to finalize their plans. Implementation of national plans started in January 2024 especially with the rollout of Men5CV in Niger and Nigeria where almost 5 million people aged 1-29 years were vaccinated during a reactive campaign.

Meningitis landscape analysis

Figure 4 shows the landscape analysis of meningitis estimated with multiple factors as epidemiology, quality of health services, climate, and introduction of meningococcal vaccines. It shows the categorization of countries of African region with 13 assigned at high risk (Nigeria, Chad, Niger, South Sudan, Cameroon, Mali, Benin, Democratic Republic of the Congo, Ghana, Central African Republic, Guinea, Angola, Ethiopia), 25 at medium risk (Burkina Faso, Togo, Uganda, South Africa, Sierra Leone, Zambia, Malawi, Guinea-Bissau, Burundi, Kenya, United Republic of Tanzania, Eritrea, Mauritania, Namibia, Senegal, Cabo Verde, Equatorial Guinea, Gabon, Lesotho, Liberia, Madagascar, Mozambique, Congo, Côte d´Ivoire, Comoros), and nine countries (Gambia, Botswana, Algeria, Eswatini, Zimbabwe, Sao Tome and Principe, Rwanda, Mauritius, Seychelles) at lower risk.

Discussion     

Meningitis suspected cases and deaths, case fatality rates, incidence

Despite the dramatic reduction of meningitis cases and deaths as a result of the MenACV rollout, the African meningitis belt continues to record non-A meningitis epidemics with thousands of cases and deaths. This result was also found in the literature [10,27,39,40]. Indeed, Trotter et al., found a 57% decline of meningitis suspected cases in nine countries (Benin, Burkina Faso, Chad, Cote d´Ivoire, Ghana, Mali, Niger, Nigeria, and Togo) five years after introduction of MenACV [10]. In Burkina Faso, Novak et al., found a 71% decline in meningitis suspected cases one year after the introduction of MenACV [41]. The CFR decreased from 2010 to 2024 from 10.8% to 5.2% as found in literature [6,7,14]. Trotter et al., Bita and Novak et al., found significant decrease of meningitis deaths before and after the introduction of MenACV [10,27,41]. This study showed that the trends of the number decreased dramatically and then remained at a plateau between 2012 and 2024 [6,9,14].

Distribution of bacterial meningitis epidemics

Despite the dramatic reduction of meningitis epidemics in the African meningitis belt resulting from MenACV introduction and rollout, countries continue to record yearly epidemics throughout the study period [10,27,39,40]. Eleven (11) countries have been recorded in meningitis epidemics from 2011 to 2024 and the most affected were Niger, Nigeria, Ghana, and Togo. Studies conducted since 2011, and the number of districts affected is decreasing. The last epidemics caused by N. meningitidis A were reported in 2014 in Guinea in two districts Siguiri and Mandiana. The reactive vaccination was conducted with MenACV and ACW, and in 205 the country rolled out MenACV nationwide. In 2017, the highest number of districts in epidemics was reported by Nigeria (37 districts) [6,7, 40,42]. This study showed as evidenced in the literature severity and magnitude of meningitis epidemics caused by meningococci, especially N. meningitidis A before the MenACV rollout and N. meningitidis serogroup C, YY, WX and S. pneumoniae after 2010. This can be explained by tremendous efforts done to detect epidemics earlier and conduct reactive vaccination with the support of vaccines provided by ICG [6,7,10,12,23,38].

Bacterial meningitis pathogen profile in Africa

The predominant pathogens that caused bacterial epidemics were N. meningitidis C, W and S. pneumoniae while before 2010 N. meningitis A caused 80-85% of epidemics [1,2,6,9,14]. The strains most circulating in meningitis belt were N. meningitidisC (ST-102017 cc, N. meningitidis W (ST C11 cc), and S. pneumoniae (serotypes 1 and 5). Retchless et al., Topaz et al., Maiden et al., Taha et al., and Vasquez et al. also found similar results. The strains that used to be found before 2010 were N. meningitidis A ST-5 cc and N. meningitidis C (ST-102017 cc, N. meningitidis W (ST C11 cc) were also found before 2010 [15,22,44,46]. These results can be explained by the MenACV rollout which resulted in the change of the bacterial profile with the disappearance of N. meningitidis A and the predominance of the following bacterial meningitis N. meningitidis C, S. pneumoniae, N. meningitidisW, Hib and N. meningitidis X.

MenACV rollout

The study found that 24 countries out of 26 of the African meningitis belt rolled out MenACV from 2010 to 2024 with over 350 million people aged 1-29 years vaccinated through preventive mass vaccination campaigns. Many authors found that millions of people were vaccinated by MenACV in meningitis belt. Tanzania and Rwanda did not introduce MenACV because of lack of evidence of meningitis A as a major public health problem. However, they envisaged strengthening meningitis surveillance.

Reactive vaccination

The introduction of enhanced and case-based surveillance of meningitis and laboratory diagnosis in the meningitis belt between 2009 and 2016 has improved early detection and confirmation of meningitis epidemics [29,40]. WHO collaborating centers have also contributed significantly to diagnosis [26, 46-48]. Apart from strengthening surveillance, laboratory capacity, and case management, particularly with the introduction of ceftriaxone in the meningitis treatment protocol, the organization of reactive vaccination has significantly contributed to reducing or stopping most meningitis outbreaks [16-27]. The prequalification of meningococcal vaccines and the existence of reserve stocks at ICG have made it possible to make available to countries that have reported meningitis epidemics. Findings in the literature as shown in this study show that mass reactive vaccinations were conducted in most of the health districts that resulted in stopping meningitis epidemics in the African meningitis belt [30-39,42,44].

Implementation of national plans to defeat meningitis by 2030 in the African region

After achieving elimination of meningitis disease caused by N. meningitidisA, countries continued to report meningococcal and pneumococcal meningitis epidemics from 2011. The regional framework to defeat meningitis by 2030, with one of the goals to eliminate bacterial meningitis epidemics caused by N. meningitidis, Hi, GBS, and S. pneumoniae will surely contribute to make Africa free of meningitis by 2030 [29]. The meningitis landscape analysis conducted was very relevant because it contributed to categorize priority countries that should implement key activities under the five pillars of the regional framework. Planning was very important to achieve before implementation. Unfortunately, due to financial resources constraints, only nine out of the 30 priority countries that attended the workshop on planning had finalized and validated their national plans. Implementation of the regional framework to defeat meningitis by 2030 started in 2024 with the rollout of Men5CV to stop meningitis epidemics caused by N. meningitidis C, W in Nigeria and Niger and improvement of surveillance and diagnosis. To catch up, advocacy should be done to mobilize more resources to finalize and validate the national plans to defeat meningitis in the 21 remaining countries and to reinforce their implementation.

Limitations: we included suspected meningitis cases and deaths (without laboratory confirmation) which might have influenced the results. For instance, some cases could have been caused by malaria, which is endemic in the sub-Saharan African meningitis belt. In a few countries, we might have underestimated the number of cases due to incomplete data because of the weak surveillance system. Only 24 countries out of 26 of the meningitis belt and Angola reported cases with a completeness rate of 92.1% and timeliness of 80%. Concerning reactive vaccination, there are few results in 2012 from Chad, Cote d´Ivoire, Benin and Ghana that are not available. However, those missing data are not significant to change the whole trends. The use of a cross-sectional study might cause information bias due to the quality of data in some countries which can have consequences on trends. However, it can be minimized because most countries the improved meningitis surveillance and data management during the past two decades.

Conclusion     

Efforts to reduce the meningitis burden from with key interventions such as MenACV rollout, strengthening epidemic detection, laboratory confirmation, reactive mass vaccination campaigns and case management with mainly inclusion of ceftriaxone, resulted in the elimination of meningitis epidemic caused by N. meningitidis A. However, a few countries of the sub-Saharan African meningitis belt continued to report bacterial meningitis epidemics caused by N. meningitidis serogroups C, W, X and S. pneumoniae. The future directions will be to implement and monitor the regional framework to defeat meningitis by 2030 in the African region endorsed during the 71^st regional committee of AFRO, especially with Men5CV rollout, and increased proportion of children vaccinated against S. pneumoniae and Hib.

Competing interests     

Tha authors declare no competing interests.

Authors' contributions     

Conceptualization: André Arsène Bita Fouda, Charles Shey Wiysonge, Anderson Latt Clément Lingani, Ado Mpia Bwaka, Sinayoko Abdoulaye, Lorenzo Pezzoli, Fernandez Katya, Mamoudou Harouna Djingarey, Shibeshi Messeret Eshetu, Djimtebaye Djimtola, Gautier Bikindou, Crépin Hilaire Dadjo, Joseph Nsiari-muzeyi Biey, Abdu Abdullahi Adamu, Franck Fortune Roland Mboussou, Benido Impouma. Writing - Original Draft: André Arsène Bita Fouda. Methodology: André Arsène Bita Fouda, Charles Shey Wiysonge, Anderson Latt. Clément Lingani, Ado Mpia Bwaka, Sinayoko Abdoulaye, Lorenzo Pezzoli, Fernandez Katya, Mamoudou Harouna Djingarey, Shibeshi Messeret Eshetu, Djimtebaye Djimtola, Gautier Bikindou, Crépin Hilaire Dadjo, Joseph Nsiari-muzeyi Biey, Abdu Abdullahi Adamu, Franck Fortune Roland Mboussou, Benido Impouma. Data curation: André Arsène Bita Fouda, Charles Shey Wiysonge, Anderson Latt, Clément Lingani, Ado Mpia Bwaka, Sinayoko Abdoulaye, Lorenzo Pezzoli, Fernandez Katya, Mamoudou Harouna Djingarey, Shibeshi Messeret Eshetu, Djimtebaye Djimtola, Gautier Bikindou, Crépin Hilaire Dadjo, Joseph Nsiari-muzeyi Biey, Abdu Abdullahi Adamu, Franck Fortune Roland Mboussou, Benido Impouma. Validation: André Arsène Bita Fouda, Charles Shey Wiysonge, Anderson Latt, Clément Lingani, Ado Mpia Bwaka, Sinayoko Abdoulaye, Lorenzo Pezzoli, Fernandez Katya, Mamoudou Harouna Djingarey, Shibeshi Messeret Eshetu, Djimtebaye Djimtola, Gautier Bikindou, Crépin Hilaire Dadjo, Joseph Nsiari-muzeyi Biey, Abdu Abdullahi Adamu, Franck Fortune Roland Mboussou, Benido Impouma. Software: André Arsène Bita Fouda. Visualization: André Arsène Bita Fouda, Formal analysis: André Arsène Bita Fouda. Writing- Reviewing and Editing: André Arsène Bita Fouda, Charles Shey Wiysonge, Anderson Latt, Clément Lingani, Ado Mpia Bwaka, Sinayoko Abdoulaye, Lorenzo Pezzoli, Fernandez Katya, Mamoudou Harouna Djingarey, Shibeshi Messeret Eshetu, Djimtebaye Djimtola, Gautier Bikindou, Crépin Hilaire Dadjo, Joseph Nsiari-muzeyi Biey, Abdu Abdullahi Adamu, Franck Fortune Roland Mboussou, Benido Impouma. All authors read and approved the final version of the manuscript.

Acknowledgments     

The authors acknowledge the WHO AFRO Member States, GAVI, BMGF, UNICEF, CDC, CDCF, USAID, SII, the regional reference laboratories and collaborating centers (Centers for Disease Control and Prevention Atlanta, Institut Pasteur in Paris, and Norwegian Institute of Public Health).

Figures     

Figure 1: evolution of meningitis suspected cases and deaths and CFR from 2004 to 2024

Figure 2: meningitis pathogen profile in the African meningitis belt from 2003 to 2024

Figure 3: menACV roll out 2010-24

Figure 4: meningitis landscape risk analysis

References