Association between Meningococcal Meningitis and Santa Ana Winds in Children and Adolescents from Tijuana, Mexico, a need for Vaccination.

Background Based on several previous studies (regional and national), Tijuana, Baja-California, Mexico (across the border from San Diego, California, USA), has shown the highest rate of Meningococcal Meningitis (MeM) in the country, however, the reason for this has not yet been known. In the “African Meningitis Belt”, the Harmattan seasons are associated with MeM outbreaks. The Santa Ana winds seasons (SAWs) are hot and dry winds (similar to Harmattan seasons) that occur seasonally in southwestern California, USA, and North of Baja-California, Mexico. Objectives Our aim was to demonstrate, as a short communication, a potential association of SAWs with MeM in Tijuana, Baja-California, Mexico, which in turn, may partially explain the high rate of this disease in the region. Methods Based on own previously published data obtained from thirteen years of active surveillance of MeM, and a 65 years review showing the occurrence of SAWs, we estimated the risk ratio (RR) of total cases number by MeM vs. bacterial non-MeM (bacterial meningitis not caused by Neisseria meningitidis) during seasons with and without SAWs. Results We found an association of SAWs seasons with MeM, but not with bacterial non-MeM (RR = 2.06, p = 0.02 (95% CI 1.1 to 3.8), which may partially explain the high endemicity of this deadly disease in this part of the globe. Conclusion This study shows a new potential climatic association with MeM, and provides more information that justifies universal meningococcal vaccination in Tijuana, Mexico.

1180. Comparing Changes in Pneumococcal Meningitis Incidence to all Invasive Pneumococcal Disease Following Introduction of PCV10 and PCV13: The PSERENADE Project

Background The introduction of higher valency pneumococcal conjugate vaccines (PCV10 and PCV13) has reduced invasive pneumococcal disease (IPD) incidence. It is unknown whether the degree of reduction differs for pneumococcal meningitis, a small subset of pneumococcal disease but a major cause of severe childhood morbidity and mortality globally. We compared the impact of PCV10/13 on pneumococcal meningitis and all IPD by estimating the changes in incidence following the introduction of PCV10/13 among children < 5 years of age. Methods Data on confirmed positive cases for pneumococcus in cerebrospinal fluid (CSF) were obtained directly from surveillance sites. PCV10/13 impact on all-serotype pneumococcal meningitis and all IPD were estimated using site-specific incidence rate ratios (IRRs) at each post-PCV10/13 year relative to the pre-PCV period, using Bayesian multi-level, mixed effects Poisson regression. All-site weighted average IRRs were estimated using linear mixed-effects regression. Results were stratified by product (PCV10 vs. PCV13) and amount of prior PCV7 use (none; some (1-3 years or 4-5 years with < 70% uptake); or many (≥ 4 years with ≥ 70% uptake). Results 40 surveillance sites (9 PCV10, 31 PCV13) in 28 countries, primarily high-income (82%) that had both CSF and IPD data were included in analyses. CSF+ accounted for 9.0% of IPD cases (IQR across sites: 6.2%-15.6%). The rate and amount of decline was generally similar between meningitis and IPD across all strata. At 5 years after PCV10/13 introduction, the IRRs across PCV7-use strata were 0.28-0.32 for pneumococcal meningitis and 0.22-0.43 for all IPD at PCV10-using sites, and 0.27-0.41 and 0.21-0.32, respectively, for PCV13-using sites. Only one site from the African meningitis belt contributed eligible data, which lacked pre-PCV data to estimate IRRs, but incidence rate of both IPD and meningitis decreased following PCV introduction. Figure 1. All-Site Weighted Average Incidence Rate Ratios, Children < 5 years * Total sites indicate the number of sites with incidence rate data included and pre/post sites indicate the number of sites with both pre− and post−PCV data to estimate site−specific IRRs for each outcome. The size of point estimates is relative to the number of sites with both pre− and post− data. ** Year 0 indicates the year of PCV10/13 introduction and year −1 indicates the last year of PCV7 use prior to PCV10/13 introduction. Conclusion Net declines in all-serotype IPD and CSF+ meningitis in children < 5 years were similar on average for both PCV10 and PCV13. Data from low-income, high-burden, and meningitis-belt regions were limited. Disclosures Maria Deloria Knoll, PhD, Merck (Research Grant or Support)Pfizer (Research Grant or Support)

Complete Genome Sequence of Streptococcus pneumoniae Strain BVJ1JL, a Serotype 1 Carriage Isolate from Malawi

Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and bacteremia. Serotype 1 is rarely carried but is commonly associated with invasive pneumococcal disease, and in the African “meningitis belt,” it is prone to cause cyclical epidemics. We report the complete genome sequence of S. pneumoniae serotype 1 strain BVJ1JL, isolated in Malawi.

An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics “outside-the-belt”

Background Bacterial meningitis occurs worldwide but Africa remains the most affected continent, especially in the "Meningitis belt" that extends from Senegal to Ethiopia. Three main bacteria are responsible for causing bacterial meningitis, i.e., N. meningitidis (Nm), S. pneumoniae and H. influenzae type b. Among Nm, serogroup A used to be responsible for up to 80 to 85% of meningococcal meningitis cases in Africa. Since 2000, other Nm serogroups including W, X and C have also been responsible for causing epidemics. This overview aims to describe the main patterns of meningitis disease cases and pathogens from 1928 to 2018 in Africa with a special focus on disease conditions “out-of-the-belt” area that is still usually unexplored. Based on basic spatio-temporal methods, and a 90-years database of reported suspected meningitis cases and death from the World Health Organization, we used both geographic information system and spatio-temporal statistics to identify the major localizations of meningitis epidemics over this period in Africa. Results Bacterial meningitis extends today outside its historical limits of the meningitis belt. Since the introduction of MenAfrivac vaccine in 2010, there has been a dramatic decrease in NmA cases while other pathogen species and Nm variants including NmW, NmC and Streptococcus pneumoniae have become more prevalent reflecting a greater diversity of bacterial strains causing meningitis epidemics in Africa today. Conclusion Bacterial meningitis remains a major public health problem in Africa today. Formerly concentrated in the region of the meningitis belt with Sub-Saharan and Sudanian environmental conditions, the disease extends now outside these historical limits to reach more forested regions in the central parts of the continent. With global environmental changes and massive vaccination targeting a unique serogroup, an epidemiological transition of bacterial meningitis is ongoing, requiring both a better consideration of the etiological nature of the responsible agents and of their proximal and distal determinants.

Impact of MenAfriVac on Meningococcal A Meningitis in Cameroon: A Retrospective Study Using Case-by-Case-Based Surveillance Data from 2009 to 2015

Meningococcal meningitis is a public health concern in Africa. Conjugated vaccine against serogroup A Neisseria meningitidis (MenAfriVac) was used in mass vaccination and was proved to have a good impact in the meningitis belt. There is a lack of information about the impact of this intervention in Cameroon after mass vaccination was undertaken. This study aimed at filling the gap in its unknown impact in Cameroon. A retrospective longitudinal study using biological monitoring data of case-by-case-based surveillance for meningitis was obtained from the National Reference Laboratories from 1 January 2009 to 20 September 2015. Immunization coverage data were obtained from Regional Public Health Delegations where immunizations took place. We compared the risks of vaccine serogroup occurrence before and after vaccinations and calculated the global impact using Halloran’s formula. Annual cases of meningitis A decreased gradually from 92 in 2011 to 34 in 2012 and then to 1 case in 2013, and since 2014, no cases have been detected. The impact was estimated at 14.48% ( p = 0.41 ) in 2012 and then at 98.63% ( p < 0.0001 ) after the end of vaccinations in 2013. This survey confirms the effectiveness of the MenAfriVac vaccine in Cameroon as expected by the WHO. The surveillance must be pursued and enhanced to monitor coming immunizations measures with multivalent conjugated vaccines for this changing threat.

Serotype Distribution of Remaining Pneumococcal Meningitis in the Mature PCV10/13 Period: Findings from the PSERENADE Project

Pneumococcal conjugate vaccine (PCV) introduction has reduced pneumococcal meningitis incidence. The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project described the serotype distribution of remaining pneumococcal meningitis in countries using PCV10/13 for least 5–7 years with primary series uptake above 70%. The distribution was estimated using a multinomial Dirichlet regression model, stratified by PCV product and age. In PCV10-using sites (N = 8; cases = 1141), PCV10 types caused 5% of cases <5 years of age and 15% among ≥5 years; the top serotypes were 19A, 6C, and 3, together causing 42% of cases <5 years and 37% ≥5 years. In PCV13-using sites (N = 32; cases = 4503), PCV13 types caused 14% in <5 and 26% in ≥5 years; 4% and 13%, respectively, were serotype 3. Among the top serotypes are five (15BC, 8, 12F, 10A, and 22F) included in higher-valency PCVs under evaluation. Other top serotypes (24F, 23B, and 23A) are not in any known investigational product. In countries with mature vaccination programs, the proportion of pneumococcal meningitis caused by vaccine-in-use serotypes is lower (≤26% across all ages) than pre-PCV (≥70% in children). Higher-valency PCVs under evaluation target over half of remaining pneumococcal meningitis cases, but questions remain regarding generalizability to the African meningitis belt where additional data are needed.

Vaccines against Meningococcal Diseases

Neisseria meningitidis is the main cause of meningitis and sepsis, potentially life-threatening conditions. Thanks to advancements in vaccine development, vaccines are now available for five out of six meningococcal disease-causing serogroups (A, B, C, W, and Y). Vaccination programs with monovalent meningococcal serogroup C (MenC) conjugate vaccines in Europe have successfully decreased MenC disease and carriage. The use of a monovalent MenA conjugate vaccine in the African meningitis belt has led to a near elimination of MenA disease. Due to the emergence of non-vaccine serogroups, recommendations have gradually shifted, in many countries, from monovalent conjugate vaccines to quadrivalent MenACWY conjugate vaccines to provide broader protection. Recent real-world effectiveness of broad-coverage, protein-based MenB vaccines has been reassuring. Vaccines are also used to control meningococcal outbreaks. Despite major improvements, meningococcal disease remains a global public health concern. Further research into changing epidemiology is needed. Ongoing efforts are being made to develop next-generation, pentavalent vaccines including a MenACWYX conjugate vaccine and a MenACWY conjugate vaccine combined with MenB, which are expected to contribute to the global control of meningitis.