Pneumococci in the African Meningitis Belt: Meningitis Incidence and Carriage Prevalence in Children and Adults Judith E. Mueller 1¤ , Seydou Yaro 2 , Macaire S. Oue ´ draogo 3 , Natalia Levina 4 , Berthe-Marie Njanpop- Lafourcade 1 , Haoua Tall 1 , Re ´ gina S. Idohou 1 , Oumarou Sanou 1 , Sita S. Kroman 1 , Aly Drabo 2 , Boubacar Nacro 3 , Athanase Millogo 3 , Mark van der Linden 4 , Bradford D. Gessner 1 * 1 Agence de Me ´decine Pre ´ventive, Paris, France, 2 Centre Muraz, Bobo-Dioulasso, Burkina Faso, 3 Centre Hospitalier Universitaire Sourou Sanou, Bobo-Dioulasso, Burkina Faso, 4 GNRC Streptococci, Aachen, Germany Abstract Background: The development of optimal vaccination strategies for pneumococcal conjugate vaccines requires serotype- specific data on disease incidence and carriage prevalence. This information is lacking for the African meningitis belt. Methods: We conducted hospital-based surveillance of acute bacterial meningitis in an urban and rural population of Burkina Faso during 2007–09. Cerebrospinal fluid was evaluated by polymerase chain reaction for species and serotype. In 2008, nasopharyngeal swabs were obtained from a representative population sample (1 month to 39 years; N = 519) and additional oropharyngeal swabs from 145 participants. Swabs were evaluated by culture. Results: Annual pneumococcal meningitis incidence rates were highest among ,6-month-old (58/100,000) and 15- to 19- year-old persons (15/100,000). Annual serotype 1 incidence was around 5/100,000 in all age groups. Pneumococcal carriage prevalence in nasopharyngeal swabs was 63% among ,5-year-old children and 22% among $5-year-old persons, but adding oropharyngeal to nasopharyngeal swabs increased the estimated carriage prevalence by 60%. Serotype 1 showed high propensity for invasive disease, particularly among persons aged $5 years. Conclusions: Serotype 1 causes the majority of cases with a relatively constant age-specific incidence. Pneumococcal carriage is common in all age groups including adults. Vaccination programs in this region may need to include older target age groups for optimal impact on disease burden. Citation: Mueller JE, Yaro S, Oue ´draogo MS, Levina N, Njanpop-Lafourcade B-M, et al. (2012) Pneumococci in the African Meningitis Belt: Meningitis Incidence and Carriage Prevalence in Children and Adults. PLoS ONE 7(12): e52464. doi:10.1371/journal.pone.0052464 Editor: Bernard Beall, Centers for Disease Control & Prevention, United States of America Received September 11, 2012; Accepted November 19, 2012; Published December 20, 2012 Copyright: ß 2012 Mueller et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The meningitis surveillance was supported by Sanofi Pasteur, Hib Initiative, PneumoADIP and the French Ministry of Foreign Affairs. The carriage study was supported by PneumoADIP and made possible through synergies with a seroprevalence study funded by the UK Medical Research Council (to Dr Caroline Trotter, Bristol University). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: JEM, HT, BMNL, RSI, and BDG work for AMP which receives unrestricted support from Sanofi Pasteur and grant specific support from Sanofi Pasteur, GSK, Merck, Pfizer, and Crucell. MVDL received research grants and honoraria from Pfizer, GSK, Sanofi Pasteur, and MSD. No other conflicts exist. For members of AMP, this relation was (and is) indirect via unrestricted funding from Sanofi Pasteur to AMP and specific project funding; no AMP authors have individual conflicts of interest (employment, consultancy, patents, products in development or marketed products etc). MVDL received consultancy and project funding, but not employment, patents, products in development or marketed products. At no time was the funder involved in analyses, interpretation of the results or manuscript writing. Altogether, these relations do not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials. * E-mail: bgessner@aamp.org ¤ Current address: Ecole des Hautes Etudes en Sante ´ Publique, Department of Epidemiology and Biostatistics, Rennes/Paris, France Introduction The African meningitis belt is located at the southern border of the Sahara and extends from Senegal to Ethiopia. It is characterized by seasonal hyperendemicity of acute bacterial meningitis during the dry season and sporadic localised and regional epidemics [1,2]. While meningitis epidemics are exclu- sively due to meningococci, seasonal hyperendemicity is due to both pneumococci and meningococci [3–6]. Pneumococcal meningitis has high incidence among older children and adults with an estimated life time risk of 0.6% and is due primarily to serotype 1 [7]. Several countries in the African meningitis belt, including Burkina Faso, plan to introduce serotype 1 containing pneumo- coccal conjugate vaccines into their routine infant immunization programs, with the goal to protect children during the first year of life, primarily from pneumonia. Given the high burden of pneumococcal meningitis in older children and adults in the African meningitis belt – and an unknown burden of pneumo- coccal pneumonia – the question arises whether the vaccination schedule for this region should be adapted to directly protect these age groups from meningitis and other pneumococcal syndromes [7]. This discussion is complex and should include biomedical, financial, logistic and sociological aspects. One approach is to PLOS ONE | www.plosone.org 1 December 2012 | Volume 7 | Issue 12 | e52464