Influence of pneumococcal vaccine on the incidence of empyema

The aim of this review is to highlight recent reports (2009) concerning empyema and the heptavalent pneumococcal conjugate vaccine.

Streptococcus pneumoniae remains the most common cause of complicated pneumonia worldwide. Moreover, the incidence of empyema is increasing in many parts of the world and nonvaccine pneumococcal serotypes have been related with this increase. The introduction of heptavalent pneumococcal conjugate vaccine has been associated with the replacement phenomenon in the nasopharynx. Replacement implies that nonvaccine serotypes acquire an ecological advantage for colonizing the nasopharynx and, consequently, increase the carriage status and, in a second step, the disease. Pneumonia with or without empyema has been the main clinical presentation related with the emergence of nonvaccine serotypes. The replacement phenomenon could be multifactorial because other factors apart from heptavalent pneumococcal conjugate vaccine can also contribute to this event.

A new generation of conjugate vaccines that include new serotypes and a wider spectrum of coverage, and the protein-based vaccines that may prevent invasion and preserve colonization, should help us to achieve a positive long-term impact of pneumococcal vaccination.