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Background: A group A meningococcal (MenA) conjugate vaccine has progressively been introduced in the African meningitis belt since 2010. A country-wide risk assessment tool, the District Prioritization Tool (DPT), was developed to help national stakeholders combine existing data and local expertise to define priority geographical areas where mass vaccination campaigns should be conducted., Methods: DPT uses an Excel-supported offline tool that was made available to the countries proposed for immunization campaigns. It used quantitative-qualitative methods, relying predominantly on evidence-based risk scores complemented by expert opinion., Results: DPT was used by most of the countries that introduced the group A conjugate vaccine. Surveillance data enabled the computation of severity scores for meningitis at the district level (magnitude, intensity, and frequency). District data were scaled regionally to facilitate phasing decisions. DPT also assessed the country's potential to conduct efficient preventive immunization campaigns while paying close attention to the scope of the geographic extension of the campaigns. The tool generated meningitis district profiles that estimated the number of vaccine doses needed. In each assessment, local meningitis experts contributed their knowledge of local risk factors for meningitis epidemics to refine the final prioritization decisions., Conclusions: DPT proved to be a useful and flexible tool that codified information and streamlined discussion among stakeholders while facilitating vaccine distribution decisions after 2011. DPT methodology may be tailored to prioritize vaccine interventions for other diseases., (© 2015 World Health Organization; licensee Oxford Journals.)

In 2012, Neisseria meningitidis serogroup W caused a widespread meningitis epidemic in Burkina Faso. We describe the dynamic of the epidemic at the subdistrict level. Disease detection at this scale allows for a timelier response, which is critical in the new epidemiologic landscape created in Africa by the N. meningitidis A conjugate vaccine.

Background: A serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine (PsA-TT, MenAfriVac) was licensed in India in 2009, and pre-qualified by WHO in 2010, on the basis of its safety and immunogenicity. This vaccine is now being deployed across the African meningitis belt. We studied the effect of PsA-TT on meningococcal meningitis and carriage in Chad during a serogroup A meningococcal meningitis epidemic., Methods: We obtained data for the incidence of meningitis before and after vaccination from national records between January, 2009, and June, 2012. In 2012, surveillance was enhanced in regions where vaccination with PsA-TT had been undertaken in 2011, and in one district where a reactive vaccination campaign in response to an outbreak of meningitis was undertaken. Meningococcal carriage was studied in an age-stratified sample of residents aged 1-29 years of a rural area roughly 13-15 and 2-4 months before and 4-6 months after vaccination. Meningococci obtained from cerebrospinal fluid or oropharyngeal swabs were characterised by conventional microbiological and molecular methods., Findings: Roughly 1·8 million individuals aged 1-29 years received one dose of PsA-TT during a vaccination campaign in three regions of Chad in and around the capital N'Djamena during 10 days in December, 2011. The incidence of meningitis during the 2012 meningitis season in these three regions was 2·48 per 100,000 (57 cases in the 2·3 million population), whereas in regions without mass vaccination, incidence was 43·8 per 100,000 (3809 cases per 8·7 million population), a 94% difference in crude incidence (p<0·0001), and an incidence rate ratio of 0·096 (95% CI 0·046-0·198). Despite enhanced surveillance, no case of serogroup A meningococcal meningitis was reported in the three vaccinated regions. 32 serogroup A carriers were identified in 4278 age-stratified individuals (0·75%) living in a rural area near the capital 2-4 months before vaccination, whereas only one serogroup A meningococcus was isolated in 5001 people living in the same community 4-6 months after vaccination (adjusted odds ratio 0·019, 95% CI 0·002-0·138; p<0·0001)., Interpretation: PSA-TT was highly effective at prevention of serogroup A invasive meningococcal disease and carriage in Chad. How long this protection will persist needs to be established., Funding: The Bill & Melinda Gates Foundation, the Wellcome Trust, and Médecins Sans Frontères., (Copyright © 2014 Daugla et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd. All rights reserved.)

Background: The epidemiology of bacterial meningitis in the African 'meningitis belt' changes periodically. In order to design an effective vaccination strategy, we have examined the epidemiological and microbiological patterns of bacterial meningitis, and especially that of meningococcal meningitis, in Niger during the period 2008-2011. During this period a mass vaccination campaign with the newly developed meningococcal A conjugate vaccine (MenAfriVac®) was undertaken., Method: Cerebrospinal fluid samples were collected from health facilities throughout Niger and analysed by culture, seroagglutination and/or speciation polymerase chain reaction, followed by genogrouping PCR for Neisseria meningitidis infections. A sample of strains were analysed by multi-locus sequence typing., Results: N. meningitidis serogroup A cases were prevalent in 2008 and 2009 [98.6% and 97.5% of all N. meningitidis cases respectively]. The prevalence of serogroup A declined in 2010 [26.4%], with the emergence of serogroup W Sequence Type (ST) 11 [72.2% of cases], and the serogroup A meningococcus finally disappeared in 2011. The geographical distribution of cases N. meningitidis serogroups A and W within Niger is described., Conclusion: The substantial decline of serogroup A cases that has been observed from 2010 onwards in Niger seems to be due to several factors including a major polysaccharide A/C vaccination campaign in 2009, the introduction of MenAfriVac® in 10 districts at risk in December 2010, the natural dynamics of meningococcal infection and the persistence of serogroup A sequence-type 7 for about 10 years. The emergence of serogroup W strains suggests that there may be a need for serogroup W containing vaccines in Niger in the coming years.

For over 100 years, large epidemics of meningococcal meningitis have occurred every few years in areas of the African Sahel and sub-Sahel known as the African meningitis belt. Until recently, the main approach to the control of these epidemics has been reactive vaccination with a polysaccharide vaccine after an outbreak has reached a defined threshold and provision of easy access to effective treatment but this approach has not prevented the occurrence of new epidemics. Meningococcal conjugate vaccines, which can prevent meningococcal carriage and thus interrupt transmission, may be more effective than polysaccharide vaccines at preventing epidemics. Because the majority of African epidemics have been caused by serogroup A meningococci, a serogroup A polysaccharide/tetanus toxoid protein conjugate vaccine (PsA-TT) has recently been developed. Results from an initial evaluation of the impact of this vaccine on meningococcal disease and meningococcal carriage in Burkina Faso have been encouraging. To review how the research agenda for meningococcal disease in Africa has been changed by the advent of PsA-TT and to define a new set of research priorities for study of meningococcal infection in Africa, a meeting of 41 scientists was held in Dakar, Senegal on April 24th and 25th 2012. The research recommendations developed during the course of this meeting are presented in this paper. The need for enhanced surveillance for meningitis in defined populations with good diagnostic facilities in African countries at risk of epidemics was identified as the highest priority. This is needed to determine the duration of protection against serogroup A meningococcal disease provided by PsA-TT and to determine the risk of disease and carriage caused by meningococci of other serogroups. Other research areas given high priority included identification and validation of serological correlates of protection against meningococcal disease and carriage, development of improved methods for detecting carriage and epidemiological studies aimed at determining the reasons underlying the peculiar epidemiology of meningococcal disease in the African meningitis belt. Minutes and working papers from the meeting are provided in supplementary tables and some of the presentations made at the meeting are available on the MenAfriCar consortium website (www.menafricar.org) and on the web site of the Centers for Disease Control (www.cdc.gov)., (Copyright © 2013. Published by Elsevier Ltd.. All rights reserved.)

A new Group A meningococcal (Men A) conjugate vaccine, MenAfriVac™, was prequalified by the World Health Organization (WHO) in June 2010. Because Burkina Faso has repeatedly suffered meningitis epidemics due to Group A Neisseria meningitidis special efforts were made to conduct a country-wide campaign with the new vaccine in late 2010 and before the onset of the next epidemic meningococcal disease season beginning in January 2011. In the ensuing five months (July-November 2010) the following challenges were successfully managed: (1) doing a large safety study and registering the new vaccine in Burkina Faso; (2) developing a comprehensive communication plan; (3) strengthening the surveillance system with particular attention to improving the capacity for real-time polymerase chain reaction (PCR) testing of spinal fluid specimens; (4) improving cold chain capacity and waste disposal; (5) developing and funding a sound campaign strategy; and (6) ensuring effective collaboration across all partners. Each of these issues required specific strategies that were managed through a WHO-led consortium that included all major partners (Ministry of Health/Burkina Faso, Serum Institute of India Ltd., UNICEF, Global Alliance for Vaccines and Immunization, Meningitis Vaccine Project, CDC/Atlanta, and the Norwegian Institute of Public Health/Oslo). Biweekly teleconferences that were led by WHO ensured that problems were identified in a timely fashion. The new meningococcal A conjugate vaccine was introduced on December 6, 2010, in a national ceremony led by His Excellency Blaise Compaore, the President of Burkina Faso. The ensuing 10-day national campaign was hugely successful, and over 11.4 million Burkinabes between the ages of 1 and 29 years (100% of target population) were vaccinated. African national immunization programs are capable of achieving very high coverage for a vaccine desired by the public, introduced in a well-organized campaign, and supported at the highest political level. The Burkina Faso success augurs well for further rollout of the Men A conjugate vaccine in meningitis belt countries., (Copyright © 2012 Elsevier Ltd. All rights reserved.)