Invasive, paediatric, vaccine strains of Streptococcus pneumoniae: are there differences in clinical characteristics?

Invasive pneumococcal infections in 777 adults caused by 'invasive' (1, 7; n=187), 'paediatric' (6, 9, 14, 19, 23; n=304) and other (n=286) serogroups were compared. Infections caused by 'invasive' strains caused pneumonia more often than other serogroups and were more often isolated from younger patients without concomitant conditions and had lower case-fatality rate than 'paediatric' and other strains. The 2 latter groups differed little from each other. Infections caused by strains in the 7-valent pneumococcal conjugate vaccine differed little from infections caused by non-vaccine types indicating that widespread use of this vaccine will not markedly change the clinical characteristics of invasive pneumococcal infections in adults.