Incidencia de la infección invasiva por Streptococcus pneumoniae en Sabadell y posible impacto de las nuevas vacunas antineumocócicas conjugadas

[Disease burden due to vaccinable diseases in the Spanish population aged less than 15 years old]

OBJECTIVES

To estimate the burden of disease due to vaccinable diseases and the relative importance of these diseases in the health of the Spanish population aged less than 15 years old.

METHODS

Disease burden was measured in disability-adjusted life years (DALYs). DALYs were computed by adding years of life lost (YLL) to years lived with disability (YLD). The DALYs of the Spanish population aged less than 15 years old were estimated for 1999 and were stratified by diseases according to the classification system of the Global Burden of Disease (adapted to the aim of the study), age group and gender. Diseases included in the childhood vaccination schedule, varicella, and pneumococcal disease were targeted for this study. The sources used were: the national mortality register to compute YLL, the Epidemiologic Surveillance National Network, hospital discharge data (CMBD) and the scientific literature to compute YLD due to vaccinable diseases, and World Health Organization estimates (Euro-A) or, when these were lacking, morbidity hospital data (Hospital Morbidity Survey) to compute the YLD due to non-vaccinable diseases.

RESULTS

The burden of disease due to vaccinable diseases was 1.2% of global DALYS (the overall DALYs rate was 46,57/1,000 habitants): excluding meningococcal disease (0.5% to 3.3%), diseases included in the vaccination schedule represented 0.00% to 0.03%, depending on age groups, except meningococcal infection (between 0.5% and 3.3%). Pneumococcal meningitis represented 0.06% to 0.65% and varicella 0.00% to 0.15%, also depending on age groups.

CONCLUSIONS

Disease burden due to vaccinable diseases is a good indicator of the health of the young population in Spain. This measure summarizes and combines information on mortality, morbidity and disability caused by diseases. The DALYs attributable to diseases included in the vaccination schedule demonstrate that immunization programs have achieved their goals.

Enfermedad invasiva por Streptococcus pneumoniae y Haemophilus influenzae serotipo b. Estudio retrospectivo de 12 años

BACKGROUND

Streptococcus pneumoniae and Haemophilus influenzae serotype b (Hib) are two of the most common causes of invasive bacterial disease in children. The introduction of a successful Hib vaccine and the emergence of penicillin-resistant pneumococci have changed the epidemiology of these bacteria over the last few years.

OBJECTIVES

To evaluate the incidence of S. pneumoniae and Hib invasive disease in children (0-15 years) admitted to our hospital during a 12-year period (January 1991-December 2002).

METHODS

We retrospectively reviewed the medical records of 101 children with isolation of S. pneumoniae and Hib in blood, cerebrospinal fluid (CSF) or synovial fluid samples during the study period.

RESULTS

SP was isolated in 81 samples (72 in blood and nine in CSF) from 73 children (72.6 % were aged < 2 years). The annual incidence per 100,000 children aged 0-2 years was 53.76 cases (95 % CI: 40.7-70.9). The most common clinical diagnosis was bacteremia (67 %). The percentage of penicillin-resistant strains was 44 %. Hib was isolated in 38 samples (26 in blood, 10 in CSF and two in synovial fluid) from 28 children (82.1 % were aged < 2 years). The most common clinical diagnosis was meningitis (35.7 %). The annual incidence per 100,000 children aged between 0-5 years dropped from 21.52 cases (95 % CI: 14.4-32) to 1.7 cases (95 % CI: 0.1-10.8) after systematic vaccination. The percentage of ampicillin-resistant strains was 63.1 %.

CONCLUSIONS

The incidence of invasive pneumococcal disease and the increased antimicrobial resistance rates of pneumococcus are two major reasons to support the routine use of pneumococcal conjugate vaccination in children. Systematic Hib vaccination since October 1998 has dramatically reduced the incidence of this disease.

Enfermedad neumocócica invasiva en la población infantil de la Comunidad Valenciana

OBJECTIVE

Pneumococcal disease is an important cause of morbidity and mortality in children. The recent authorization of the heptavalent conjugate vaccine has increased interest in this disease. The objective of this study was to identify the epidemiological and clinical characteristics of this disease, as well as its outcome in the pediatric population of the Autonomous Community of Valencia.

METHOD

Data were obtained from the medical records of children aged less than 15 years who were positive for pneumococcus isolation on admission to hospital between 1996 and 2000. All the public hospitals of the Autonomous Community of Valencia were included. Changes in incidence were evaluated by comparing rates and outcomes (sequelae and lethality) through frequency and age distribution.

RESULTS

One hundred twenty-seven cases were registered, giving a mean annual rate of 3.89/105 inhabitants aged less than 15 years. The rate was 20.14 in children aged less than 2 years. A total of 29.1% of the children had previous health problems. The main clinical manifestations included sepsis/bacteremia (38%), pneumonia (31%) and meningitis (24%). At discharge sequelae were present in 10 children, 75% of whom were aged less than 2 years. Eight children died (6.3% lethality).

CONCLUSIONS

In the period and region studied, pneumococcal infection was present mainly in children aged less than 2 years and in those with previous health problems. In the last few years, mortality has increased. Thus, inclusion of pneumococcal disease in the epidemiological surveillance system would be appropriate to achieve more precise estimations of its epidemiological patterns and to determine whether the conjugate vaccine represents a solution to the problems currently associated with this bacteria.