[Coverage of the 23-valent pneumococcal vaccine in those older than 64 years of age in the region of Castellon and Valencia, Spain]

Abstract

The different serotypes of Streptococcus pneumoniae isolated from adults aged over 64 years in the Valencia and Castellon health region of Spain from June 1999 to December 2003 were analyzed. A total of 163 strains were evaluated; 58.3% were invasive, 47.24% were from respiratory source, and 4.9% were from exudates. The greatest percentage of samples was obtained from the group of patients aged 65 to 75 years (60.7%), while the lowest percentage was obtained from the group of patients aged over 85 years (10.4%). In the latter group, 53% of the strains were invasive and 29.4% were isolated from sputum. A total of 21 serotypes were identified, with the most common (> 3%) being: serotype 3 (22.1%); serotype 19 (12.9%); serotype 6 (12.3%); serotype 9 (8.6%); serotype 14 (10.4%); serotype 23 (8%); serotype 29 (3.7%); and serotype 18 (3.1%). Serotype 3 was the most common serotype found in all samples, with the exception of exudate, while serotype 23 was not isolated in blood. In this population group, the coverage of the 23-valent vaccine was 88.4%. Serotypes not included in this vaccine but isolated from invasive samples were serotypes 16, 24, 29 and 35. No changes were observed in serotype distribution over the 4-year period of the study. However, it is necessary to continue epidemiological monitoring to determine whether serotype substitution occurs.