Seroprevalence of antibodies against serogroup C meningococci in the region of Valencia, Spain: Impact of meningococcal C conjugate vaccination.

BACKGROUND AND AIMS: Meningococcal C conjugate (MCC) vaccination programs provide direct and indirect protection against meningococcal disease. However, a decrease in the antibodies could affect herd immunity. We conducted a seroprevalence study to assess the immunity in subjects 8-12years after different MCCV vaccination programs were launched and evaluated the impact of vaccination on seroprotection. METHODS: Seroepidemiological study conducted from October 2010 to April 2012 in the region of Valencia, Spain. Sample size was not proportional to the population but to the expected seroprotection by age group. Sera from subjects that were≥3years old were tested using a standardized complement-mediated serum bactericidal antibodies (SBA) assay. Age-stratified proportions of subjects with SBA titers≥8 were considered seroprotected and evaluated. A multivariate logistic regression model was performed to evaluate the impact of vaccination on the seroprotection. RESULTS: Serum samples from 1880 subjects were collected. In total, 523 (27.8%) of the 1880 subjects and 446 (31.2%) of the 1430 subjects<30years (targeted to any vaccination campaign) showed protective SBA titers. The highest percentage of seroprotected subjects (67.8%, 95%CI 56.9-77.4) was observed in those that were vaccinated in a catch-up campaign at 10-13years of age (20-21years old at the time of blood sampling). Those scheduled for immunization in infancy at 2, 4 and 6months of age (7-8years at blood sample) represented the lowest (7.1%, 95% CI 3.3-13.1) number of seroprotected subjects. Having received one vaccine dose after 12months of age was associated with increased seroprotection. The present study revealed a positive correlation between the increasing age at vaccination and longer duration of seroprotection. CONCLUSION: Only one in three subjects who were vaccinated with MCC vaccine was seroprotected after 8-12years. These findings emphasize that seroprevalence studies are essential to identify susceptible cohorts and to inform vaccine policy.

The Global Meningococcal Initiative: global epidemiology, the impact of vaccines on meningococcal disease and the importance of herd protection.

INTRODUCTION: The 2015 Global Meningococcal Initiative (GMI) meeting discussed the global importance of meningococcal disease (MD) and its continually changing epidemiology. Areas covered: Although recent vaccination programs have been successful in reducing incidence in many countries (e.g. Neisseria meningitidis serogroup [Men]C in Brazil, MenA in the African meningitis belt), new clones have emerged, causing outbreaks (e.g. MenW in South America, MenC in Nigeria and Niger). The importance of herd protection was highlighted, emphasizing the need for high vaccination uptake among those with the highest carriage rates, as was the need for boosters to maintain individual and herd protection following decline of immune response after primary immunization. Expert commentary: The GMI Global Recommendations for Meningococcal Disease were updated to include a recommendation to enable access to whole-genome sequencing as for surveillance, guidance on strain typing to guide use of subcapsular vaccines, and recognition of the importance of advocacy and awareness campaigns.

Vacunas y Enfermedad Meningocócica Invasiva / Vaccines and invasive meningococcal disease

La enfermedad meningocócica invasiva tiene a menudo consecuencias devastadoras y está causada por el microorganismo Neisseria meningitidis, comúnmente conocido como meningococo. En estos momentos contamos con herramientas eficaces para la prevención de muchos de los serogrupos causantes de enfermedad (A.C, Y y W135) con distintas presentaciones y características, pero, pese a los esfuerzos realizados, aún no contamos con una vacuna eficaz frente al serogrupo B, que está asociado a más del 90% de los casos clínicos. No obstante en el futuro inmediato es muy posible que podamos utilizar preparados vacunales también frente a este serogrupo. Dada la gravedad de la enfermedad y el riesgo potencial que entraña, es recomendable que todo el personal de laboratorio, tanto en ambiente hospitalario como fuera del hospital, que tenga exposición a cultivos, suspensiones etc de cepas de meningococo aisladas de casos clínicos reciba vacuna conjugada tetravalente como parte de su programa de prevención laboral. Así mismo otro personal sanitario con riesgo debería recibir información y/o vacunación en los mismo términos. Personal militar en misiones internacionales y trabajadores de ONGs y algún colectivo (misiones diplomáticas, etc) así como viajeros a áreas de hiper endemia están claramente incluidos en los grupos en los es recomendable utilizar la prevención. En todos los casos es recomendable la utilización de las nuevas vacunas conjugadas antes que las vacunas de polisacárido purificado, que se han asociado a fenómenos de hipo-respuesta tras sucesivas dosis (AU)

Invasive meningococcal disease often has devastating consequences and is caused by the organism Neisseria meningitidis, commonly known as meningococcus. We now have effective tools for the prevention of many disease causing serogroups (A, C, Y, and W 135),. With various presentations and features, byt despite these efforts, we have not yet an effective vaccine against serogroup B, which is associated with more than 80% of clinical cases. But in the immediate future is very possible that we can also use vaccines against this serogroup. Given the severity of the disease and potential risk involved, it is recommended that all laboratory personnel in both hospital environment and outside the hospital, which has exposure to suspensions of strains isolated from clinical cases receive tetravalent meningococcal conjugate vaccines as part of their workplace prevention program. Likewise other health personnel at risk should receive information and/or vaccination in the same terms. Military personnel in international missions. NGOs workers and other groups (diplomatic missions, etc) and travelers to hyper endemic areas are clearly included in the group that should use prevention. In all cases we recommend the use of new conjugate vaccines before purified polysaccharide vaccines, which have been associated with hypo-response phenomena after successive doses (AU)

[Current situation of the epidemiology of meningococcal disease]. / Situación actual de la epidemiología de la enfermedad meningocócica.

Neisseria meningitidis, the etiological agent of all forms of meningococcal disease, is still a cause for concern among society in general and especially among health workers. Several of its antigens have been used in strain characterization, and some have served as the basis for the development of vaccines. In this sense, the best known are the capsular polysaccharide, which defines the serogroups, the outer membrane protein of class 2/3, used for serotype classification, and the class 1 porins, defining the serosubtype. During the last 30 years, most cases of meningococcal disease in Spain have been due to serogroup B strains, with the exception of 1996 and 1997, when serogroup C cases became the most frequent. The capsular polysaccharide has been successfully used in the development of conjugate vaccines highly effective against A, Y and W135 serogroups and particularly against serogroup C isolates. The development of a vaccine against serogroup B strains for routine immunization is still uncertain. However, the use of specific vaccines based on antigenic formulations of class 1 protein, to be applied in epidemic situations, is closer to becoming a reality. Because of the current absence of a universal vaccine against N. meningitidis, specific surveillance programs are required to evaluate the importance of recombination processes affecting capsular expression. This type of event could produce new strain variants able to avoid the immunological response generated after vaccination.

Situación actual de la epidemiología de la enfermedad meningocócica / Current situation of the epidemiology of meningococcal disease

Neisseria meningitidis, agente causal de enfermedad meningocócica en todas sus variantes de presentación clínica, es aún un motivo de alerta social y un importante foco de atención para el personal sanitario. Muchos de sus antígenos se han utilizado en la caracterización de las cepas y algunos han constituido la base para el desarrollo de vacunas. En este sentido, los más conocidos son el polisacárido capsular, que define el serogrupo, las proteínas de membrana externa de clase 2/3, utilizadas en la clasificación en serotipos, y las porinas de clase 1 que definen el serosubtipo. En los últimos 30 años, las cepas de serogrupo B han constituido el grupo mayoritario entre los aislados de casos clínicos, excepto durante los años 1996 y 1997, en los que el serogrupo C pasó a ser mayoritario. El polisacárido capsular se ha utilizado con éxito en el desarrollo de vacunas conjugadas altamente eficaces para los serogrupos A, Y y W135 y, especialmente, frente a meningococos de serogrupo C. El desarrollo de una vacuna de utilización en calendario vacunal frente a serogrupo B aún es incierto. No obstante, la utilización de vacunas específicas con formulación de proteínas de clase 1, de aplicación en situación de epidemias, constituye una realidad más cercana. La imposibilidad actual de aplicar vacunas universales frente a N. meningitidis obliga a extremar la vigilancia para poder evaluar la importancia de procesos de intercambio genético capsular que podrían producir nuevas variantes que evadieran la respuesta inmunitaria generada por la vacunación

Neisseria meningitidis, the etiological agent of all forms of meningococcal disease, is still a cause for concern among society in general and especially among health workers. Several of its antigens have been used in strain characterization, and some have served as the basis for the development of vaccines. In this sense, the best known are the capsular polysaccharide, which defines the serogroups, the outer membrane protein of class 2/3, used for serotype classification, and the class 1 porins, defining the serosubtype. During the last 30 years, most cases of meningococcal disease in Spain have been due to serogroup B strains, with the exception of 1996 and 1997, when serogroup C cases became the most frequent. The capsular polysaccharide has been successfully used in the development of conjugate vaccines highly effective against A, Y and W135 serogroups and particularly against serogroup C isolates. The development of a vaccine against serogroup B strains for routine immunization is still uncertain. However, the use of specific vaccines based on antigenic formulations of class 1 protein, to be applied in epidemic situations, is closer to becoming a reality. Because of the current absence of a universal vaccine against N. meningitidis, specific surveillance programs are required to evaluate the importance of recombination processes affecting capsular expression. This type of event could produce new strain variants able to avoid the immunological response generated after vaccination