Seroprevalence of bactericidal antibodies against serogroup B and C Meningococci in a University Hospital

Meningococcus serogroup B (MenB), clonal complex 32 (cc 32), was the Brazilian epidemic strain of meningococcal disease (MD) in the 1990’s. Currently, meningococcus serogroup C (MenC), cc 103, is responsible for most of the cases of the disease in Brazil. The aim of this study was to investigate the seroprevalence of bactericidal antibody (SBA) against representative epidemic strains of MenC, (N753/00 strain, C:23:P1.22,14-6, cc103) and MenB, (Cu385/83 strain, B:4,7:P1.15,19, cc32) in students and employees of a university hospital in the State of Rio Grande do Sul (RS, Brazil). A second MenC strain (N79/96, C:2b:P1.5-2,10, cc 8) was used as a prototype strain of Rio de Janeiro’s outbreak that occurred in the 1990’s. Our previous study showed a 9% rate of asymptomatic carriers in these same individuals. A second goal was to compare the SBA prevalence in meningococcal carriers and non-carriers. Fifty-nine percent of the studied population showed protective levels of SBA titers (log2≥2) against at least one of the three strains. About 40% of the individuals had protective levels of SBA against N753/00 and Cu385/83 strains. Nonetheless, only 22% of the individuals showed protective levels against N79/96 strain. Significantly higher antibody levels were seen in carriers compared to non-carriers (P≤0.009). This study showed that, similar to other States in Brazil, a MenC (23:P1.22,14-6, cc103) strain with epidemic potential is circulating in this hospital. Close control by the Epidemiological Surveillance Agency of RS of the number of cases of MD caused by MenC strains in the State is recommended to prevent a new disease outbreak.

Impacto da implantação da vacina conjugada na incidência de meningite meningocócica do tipo C em crianças menores de cinco anos no Sul de Santa Catarina / Impact of the conjugated vaccine implementation on the incidence of meningococcal meningitis type C in children under five in southern Santa Catarina

Introdução: A Doença Meningocócica (DM) é uma infecção bacteriana aguda causada pela Neisseria meningitidis. Acomete principalmente crianças menores de cinco anos, sobretudo as menores de um ano. Suas manifestações clínicas variam desde doença leve até síndrome séptica e/ou meningite. Diante da letalidade da doença, o Ministério da Saúde incluiu no calendário vacinal, no segundo semestre de 2010, a vacina adsorvida meningocócica C (conjugada). Justificativa: Considerando a recente implementação da vacina no serviço público, é necessário avaliar o impacto desta na saúde da população. Este estudo tem como objetivo descrever a ocorrência de Meningite Meningocócica do tipo C em crianças menores de cinco anos na macrorregional Sul do Estado de Santa Catarina dois anos antes (2008 e 2009) e dois anos depois (2011-2012) após a campanha vacinal contra o meningococo C, realizada no ano de 2010. Métodos: Este é um estudo observacional do tipo transversal. Resultados/Discussão: No período estudado, houve apenas cinco casos confirmados de doença meningocócica. O baixo número de casos deve-se provavelmente à ampla utilização da vacina em clínicas particulares já em anos anteriores aos estudados. Nenhuma criança morreu devido à meningite meningocócica ou meningococcemia, sendo que estudos no Brasil em períodos anteriores à vacinação mostraram letalidade em torno de 20%. Conclusão: O menor número de casos e menor mortalidade pela DM demonstram maior efetividade da Vigilância Epidemiológica e efetividade do diagnóstico precoce (AU)

Introduction: Meningococcal disease (MD) is an acute bacterial infection caused by Neisseria meningitidis. It mainly affects children under five years of age, especially children under one year. Its clinical manifestations range from mild disease to septic syndrome and/or meningitis. Given the lethality of the disease, the Ministry of Health included the adsorbed meningococcal C vaccine (conjugated) in the vaccine calendar in the second half of 2010. Justification: Considering the recent implementation of the vaccine in the public service, it is necessary to evaluate its impact on the health of the population. This study aims to describe the occurrence of Meningococcal Meningitis type C in children under five years of age in the southern macro-region of the State of Santa Catarina two years before (2008-2009) and two years after (2011-2012) the vaccination campaign against meningococcus C carried out in 2010. Methods: This is an observational cross-sectional study. Results/Discussion: In the study period, there were only five confirmed cases of meningococcal disease. The low number of cases is likely due to the wide use of the vaccine in private clinics already years before those studied here. No child died due to meningococcal meningitis, and studies in Brazil prior to vaccination show lethality around 20%. Conclusion: The lower number of cases and lower mortality due to MD demonstrate greater effectiveness of the Epidemiological Surveillance and the effectiveness of early diagnosis (AU)

Análise crítica das recomendações do uso das vacinas meningocócicas conjugadas / A critical appraisal of the recommendations for the use of meningococcal conjugate vaccines

OBJETIVOS: Analisar a epidemiologia da doença meningocócica no Brasil e o impacto que as recentes evidências acumuladas com a incorporação das vacinas meningocócicas C conjugadas nos programas de imunização podem ter nas diferentes estratégias de uso dessas vacinas. FONTES DOS DADOS: Revisão nas bases de dados MEDLINE, SciELO e LILACS no período de 2000 a 2011. SÍNTESE DOS DADOS: No Brasil, a doença meningocócica é endêmica, com ocorrência periódica de surtos. Os maiores coeficientes de incidência ocorrem em lactentes, sendo o sorogrupo C responsável pela maioria dos casos, motivando a introdução da vacina meningocócica C conjugada no Programa Nacional de Imunizações, em 2010, para crianças menores de 2 anos. A introdução das vacinas meningocócicas C conjugadas nos programas de imunização na Europa, Canadá e Austrália mostrou-se efetiva, com dramática redução na incidência de doença causada pelo sorogrupo C, não apenas nos vacinados, mas também em não vacinados. A efetividade em longo prazo dessas vacinas mostrou-se dependente de uma combinação de persistência de anticorpos, memória imunológica e proteção indireta. Recentes evidências indicando que a persistência de anticorpos não é duradoura em crianças pequenas imunizadas e que a memória imunológica não é rápida o suficiente para protegê-las contra a doença enfatizam a importância da proteção indireta para manutenção da população protegida. CONCLUSÕES: A rápida queda de títulos de anticorpos em crianças vacinadas nos primeiros anos de vida sugere a necessidade de incorporarmos doses de reforço antes da adolescência, especialmente em locais como o Brasil, onde ainda não contamos com o efeito da proteção indireta da população.

OBJECTIVES: To assess the epidemiology of meningococcal disease (MD) in Brazil and the impact that recent evidence and lessons learned from the introduction of meningococcal C conjugate (MCC) vaccines into immunization programs may have on different strategies of vaccine use. SOURCES: Non-systematic review of the MEDLINE, SciELO and LILACS databases covering the period from 2000 to 2011. SUMMARY OF THE FINDINGS: Meningococcal disease is endemic in Brazil, with periodic occurrence of outbreaks. Most cases are associated with serogroup C and the highest incidence rates are observed in infants, encouraging the introduction of MCC vaccine in the National Immunization Program in 2010 for children under 2 years old. The introduction of MCC vaccines into immunization programs in Europe, Canada and Australia proved to be effective, with dramatic reduction in the incidence of serogroup C meningococcal disease, not only in the vaccinated, but also in the unvaccinated individuals. Long-term effectiveness of MCC vaccines was dependent on a combination of antibody persistence, immunologic memory and herd protection. Recent evidence indicating that antibody persistence is not long-lasting in young immunized children, and that immunologic memory is not fast enough to protect them against the disease, emphasize the importance of herd protection to maintain the population protected. CONCLUSIONS: The rapid decline of antibody titers in children vaccinated in the first years of life suggests the need to incorporate booster doses before adolescence, especially in locations like Brazil, where the immunization program did not incorporate catch-up campaigns including adolescents, lacking the herd immunity effect.

Critical analysis of old and new vaccines against N. meningitidis serogroup C, considering the meningococcal disease epidemiology in Brazil

Worldwide, the impact of meningococcal disease is substantial, and the potential for the introduction and spread of more virulent strains of N. meningitidis or strains with increased resistance to current antibiotics causes concern, making prevention essential. OBJECTIVES: Review the indications for meningococcal disease vaccines, considering the epidemiological status in Brazil. METHODS: A critical literature review on this issue using the Medline and Lilacs databases. RESULTS: In Brazil, MenB and MenC were the most important serogroups identified in the 1990s. Polysaccharide vaccines available against those serogroups can offer only limited protection for infants, the group at highest risk for meningococcal disease. Additionally, polysaccharide vaccines may induce a hypo-responsive state to MenC. New meningococcal C conjugate vaccines could partially solve these problems, but it is unlikely that in the next few years a vaccine against MenB that can promote good protection against multiple strains of MenB responsible for endemic and epidemic diseases will become available. CONCLUSIONS: In order to make the best decision about recommendations on immunization practices, better quality surveillance data are required. In Brazil, MenC was responsible for about 2,000 cases per year during the last 10 years. New conjugate vaccines against MenC are very effective and immunogenic, and they should be recommended, especially for children less than 5 years old. Polysaccharide vaccines should be indicated only in epidemic situations and for high-risk groups. Until new vaccines against MenC and MenB are available for routine immunization programs, the most important measure for controlling meningococcal disease is early diagnosis of these infections in order to treat patients and to offer chemoprophylaxis to contacts