Objectives: To assess the epidemiological characteristics of invasive pneumococcal disease (IPD) in children in Gipuzkoa (Spain) as well as the serotype distribution among these episodes and to analyze the potential impact of new conjugate vaccines.
Methods: We performed a retrospective study of cases of IPD in the pediatric population (< 15 years) between 1981 and 2001. Patients were included if blood, cerebrospinal, joint or peritoneal fluid isolates were culture-positive for Streptococcus pneumoniae.
Results: One hundred twenty-nine episodes (30 meningitis, 39 bacteremic pneumonia, 7 peritonitis, 1 arthritis and 52 bacteremia without focus) were identified. The incidence of IPD in children increased throughout the study period and from 1999-2001 was 12.6 cases per 100,000/ year in children aged < 15 years, 34.5 in those < 5 years, 48.4 in those < 2 years and 40.8 in infants < 2 months. The incidence of pneumococcal meningitis was similar throughout the study period (1981-2001): 1.3 in children aged < 15 years, 3.5 in those < 5 years, 8.1 in those < 2 years and 10.2 in infants < 2 months. From 1989 to 2001 mortality was 1 % (1/98 cases). The pneumococcal serotypes and serogroups present in the 7-valent vaccine accounted for 60.5 % and 70.9 % of the cases (9-valent vaccine: 70.2 % and 80.6 %; 11-valent vaccine: 76.6 % and 87.2 %). From 1999-2001, penicillin resistance was 35.4 % and erythromycin resistance was 38.7 %.
Conclusions: The incidence of IPD in children in Gipuzkoa has increased in the last few years, with rates similar to those in other European countries. Continued surveillance is required to assess the impact of the new conjugate vaccines on this infection.