Case−Control Study of Risk Factors for Meningococcal Disease in Chile

Abstract

An outbreak of meningococcal disease with a case-fatality rate of 30% and caused by predominantly serogroup W of Neisseria meningitidis began in Chile in 2012. This outbreak required a case−control study to assess determinants and risk factors for infection. We identified confirmed cases during January 2012−March 2013 and selected controls by random sampling of the population, matched for age and sex, resulting in 135 case-patients and 618 controls. Sociodemographic variables, habits, and previous illnesses were studied. Analyses yielded adjusted odds ratios as estimators of the probability of disease development. Results indicated that conditions of social vulnerability, such as low income and overcrowding, as well as familial history of this disease and clinical histories, especially chronic diseases and hospitalization for respiratory conditions, increased the probability of illness. Findings should contribute to direction of intersectoral public policies toward a highly vulnerable social group to enable them to improve their living conditions and health.

Carriage of Neisseria Meningitidis in Low and Middle Income Countries of the Americas and Asia: A Review of the Literature

“…In addition, disease caused by MenW began to increase in Chile in 2010, accounting for 58% of all cases by 2012 [28]. This was a hypervirulent strain often attributed to sequence type 11 clonal complex (cc11) [21], which caused an increase in mortality and long-term disabling sequelae [28].…”

“…In addition, disease caused by MenW began to increase in Chile in 2010, accounting for 58% of all cases by 2012 [28]. This was a hypervirulent strain often attributed to sequence type 11 clonal complex (cc11) [21], which caused an increase in mortality and long-term disabling sequelae [28]. The incidence rate was highest in very young infants, with a second peak observed in older adults (aged [ 60 years); the number of cases of MenW disease in adolescents was very low [21].…”

“…The incidence rate was highest in very young infants, with a second peak observed in older adults (aged [ 60 years); the number of cases of MenW disease in adolescents was very low [21]. A mass vaccination campaign with a meningococcal quadrivalent vaccine was accordingly implemented by the Chilean Ministry of Health in October 2012 for children aged 9 months to 5 years, followed by the introduction of the meningococcal quadrivalent conjugate vaccine (MenACWY) into routine vaccination schedules at 12 months of age in 2014 [21,[28][29][30][31].…”

Plan de acción nacional frente a la emergencia de la cepa W-135 responsable de enfermedad meningocócica invasora en Chile, 2012-2013

“…Frente a la aparición y aumento de casos de EMI por MenW, la estrategia de control fue la identificación y bloqueo inmediato de los contactos. En el año 2010 se notificaron 47 Al ISP, como laboratorio de referencia nacional, le correspondió capacitar a los microbiólogos que se desempeñaron en la red pública y privada de laboratorios, en el diagnóstico de EMI y en la confirmación de los casos mediante identificación de serogrupos, así como también estudiar la susceptibilidad antimicrobiana. Se incorporaron las técnicas de PFGE y MLST para identificar distintos linajes genéticos que componen la estructura poblacional de patógenos distribuidos globalmente 30,42 .…”

“…Estos estudios demostraron que nos encontrábamos frente a un clon semejante al descrito en el brote del Hajj 30 , pero con distintos mecanismos de virulencia, como el alelo 22 para el gen de la fHbp 29 , lo que podría explicar su mayor asociación con sepsis y letalidad 26,27 ; que la portación de Nm en adolescentes entre 10 a 19 años era de 6,5% y de 4,0% para aquellos entre 18 a 24 años, con un predominio de Nm no seroagrupables, seguido de MenB 45,46 . El análisis de casos y controles identificó las condiciones de vida desfavorables, como la pobreza, los espacios reducidos, el hacinamiento y las enfermedades respiratorias como los principales factores de riesgo 47 .…”