The burden of hospitalizations for meningococcal infection in Spain (1997–2008)
Highlights
► We studied the burden of hospitalization for meningococcal infection in the general population in Spain using the surveillance system for hospital data. ► We compare it to the microbiology information system and the notifiable diseases system. ► The hospitalization rate was 2.33, 1.23 and 1.29 cases per 100,000 for invasive meningococcal disease, meningococcal meningitis and meningococcemia. ► Although an important decrease in morbidity and mortality occurred in the last twelve years, it continues being a major cause of hospitalization and death, especially in children younger than 2.
Introduction
Meningococcal infection (MI) remains an important public health problem worldwide, not only because of high lethality, but also severe disabling sequelae such as cognitive deficiencies or hearing loss [1], [2], [3]. Developing countries carry the major burden of the disease, but MI still has an incidence of 1.01 per 100,000 population in European countries [4]. The meningococcus commonly colonizes nasopharynx asymptomatically, but can occasionally cause invasive disease. Serogroups A, B, C, W135, X and Y are the majorly responsible for invasive disease. Meanwhile B and C are the most important serogroups in western countries, serogroup A is the leading cause of meningococcal infection in Africa.
Currently, several vaccines that offer protection against meningococcal disease are available. Polysaccharide vaccines against meningococcal serogroups A, C, Y and W135 have been available for several decades but induce poor immunogenicity in young children and minimal effects on nasopharyngeal carriage. On the other hand, the introduction of the conjugate serogroup C meningococcal vaccine has dramatically changed the epidemiology of the disease in industrialized countries, showing potential for broader control with A, C, Y and W135 conjugates, and leaving serogroup B as the predominant cause of disease [5].
Despite the recognised concern and social alarm caused by meningococcal disease, longitudinal evaluation of meningococcal disease trends and effects of vaccines on its epidemiology is still needed. Hospital discharge databases are useful for establishing disease burden, as they provide a complete record of all hospitalizations and, in general, are not subject to the limitations of outpatient surveillance systems, such as under-diagnosis or deficiencies in reporting. Another advantage of these databases is the standardized diagnosis code lists that enable secular trend analysis of incident disease for a given population. The Spanish centralized discharge database, which covers an estimated 98% of hospitals of the National Health Care System (covering almost all the Spanish population), can give a reasonable approximation to the burden of meningococcal infections related hospitalizations. Furthermore, this database has been shown to be a reliable tool for enumerating cases of different infectious diseases that required hospitalization [6], [7], [8].
This epidemiological retrospective survey aims to provide population-based estimates of the burden of hospitalization for meningococcal infection in the general population in Spain during a twelve-year period (1997–2008).
Section snippets
Materials and methods
This retrospective study used the national surveillance system for hospital data (Conjunto Mínimo Básico de Datos; CMBD) maintained by the Ministry of Health. This system uses clinical codes from the Spanish version of the 9th International Classification of Diseases (Modificación Clínica Clasificación Internacional de Enfermedades; CIE-9-MC) and covers an estimated 98% of public hospitals. Compulsory health insurance covers an estimated 99.5% of the Spanish population, but even persons not
Results
A total of 11,611 hospital discharges for meningococcal infections (MI) (ICD 9 CM 036; any listed diagnosis position) in the general population were reported during the 12-year study period. This corresponds to a hospitalization rate of 2.33 (CI 95%: 2.28–2.37) hospitalizations per 100,000 inhabitants/year during the study period. The hospitalization rate decreased significantly (p< 0.001) from 4.26 (CI 95%: 4.06–4.47) hospitalizations per 100,000 inhabitants in 1997 to 1.56 (CI 95%: 1.45–1.68)
Discussion
This study reflects the impact of past and current public health control and preventive measures on the meningococcal disease burden by reporting the population-based estimates of the burden of hospitalizations due to meningococcal infection and specifically meningococcal meningitis and meningococcemia in general population in Spain from 1997 to 2008. These hospitalizations are a measure of the most severe cases. A mass vaccination of children and adolescents up to 19 years old with A + C
Acknowledgement
To the Subdirección General del Instituto de Información Sanitaria for providing with the information in which this study is based.
References (22)
- et al.
Global epidemiology of meningococcal disease
Vaccine.
(2009) - et al.
Hospital admissions for meningococcal infections in Madrid, Spain (1997–2005)
Med Clin (Barc)
(2010) - et al.
Epidemiology of pneumococcal meningitis hospitalisations in pediatric population in Spain (1998–2006)
Vaccine
(2009) - et al.
Incidence of invasive meningococcal diseases in children in Northern France: usefulness and limits of the discharge code database for correcting compulsory notification data
Arch Pediatr
(2009) - et al.
Meningococcal vaccines
- et al.
Meningococcal disease
N Engl J Med
(2001) - Bilukha, Rosenstein. Prevention and control of meningococcal disease. MMWR. Recommendations of the Advisory Committee...
- et al.
The epidemiology of meningococcal disease and the impact of vaccines
Expert Rev Vaccines
(2010) - et al.
Hospital admissions for meningococcal infection in Spain (1997–2005)
J Infect
(2009) - Ministerio de Sanidad y Consumo. Clasificación internacional de enfermedades 9 revisión, modificación clínica. 1996. p....