Eight years of active proposal of pneumococcal 23-valent polysaccharide vaccine: Survey on coverage rate among elderly and chronic patients

Background: Streptococcus pneumoniae, lancet-shaped, gram-positive, facultative anaerobic organisms, are common inhabitants of the respiratory tract and may be isolated from the nasopharynx of 5% to 70% of healthy adults. Objective: The aims of the study were to estimate the vaccination coverage for pneumococcal 23-valent polysaccharide vaccine and to assess the impact its introduction in the Italian region of Puglia, where a program to provide this vaccination has been operative since 2000. Methods: Estimation of the coverage for pneumococcal 23-valent polysaccharide vaccine was implemented by a 2-step study consisting of data collection from local health unit vaccination registers between 2000 and 2008 in Puglia and of a cluster sampling study among general practitioners to validate routine data collected during the first step. Moreover, hospitalization for invasive pneumococcal diseases was studied. Results: From 2000 to 2004, among individuals >= 65 years, the overall coverage rate estimated by routine data amounted to 26.3%; between 2005 and 2007, annual coverage rates did not exceed 8%/year. Between 2002 and 2007, the overall coverage rate estimated by interviewing general practitioners was 46.6% (95% confidence interval: 39.9-53.4). The coverage rate in chronic patients by routine data was approximately 23%, whereas the rate provided by general practitioners was 17.6% (95% confidence interval: 12.5-22.8). From 2001 to 2007, hospitalization data did not show a reduction in invasive pneumococcal disease trends among the elderly population in Puglia. Conclusion: The results of this study demonstrate the need for improving vaccine coverage and implementing new immunization strategies and practices.