Invasive pneumococcal infections in infants up to three years of age: results of a longitudinal surveillance in North-East Italy.

Pneumococcus is considered one of the main causes of the infections acquired in the community setting and also seems to be the most frequent cause of community-acquired pneumonia in children under 5 years of age. To establish suitable preventive measures as vaccination policy, it would be important to document the incidence of IPD. The main feature of this study was that it demanded a cooperative effort between family pediatricians and those working in the hospitals to estimate the real burden of IPD in children aged 0-36. From 1 January 2003 to 31 December 2003, a prospective active surveillance of clinical cases due to S. pneumoniae was conducted by 87 specifically-trained sentinel pediatricians [all family pediatricians] randomly selected from among those working in North-East Italy. Suspected pneumococcal infections were confirmed by blood cultures at the laboratories of the hospitals involved in the study. 32 cases were suspected, 12 of those proved positive on blood culture and 6 of these 12 confirmed cases were hospitalized. 2 were cases of meningitis, 1 of pneumonia and 9 of bacteremia. The cumulative annual incidence was 58.9 cases/100,000 infants aged 0-36 months (95% CI 30.38-102.71), meaning that North-East Italy can be classified as a mesoendemic area. This study demonstrated that the incidence of IPD in infants aged (0-36 months) is often under-estimated, documenting the importance of prospective active surveillance for assisting rational choices for public health issues.