Five-fold increase in pediatric parapneumonic empyema since introduction of pneumococcal conjugate vaccine.

A retrospective review of medical records for all pediatric parapneumonic empyema (PPE) patients admitted to our hospital from 1996 to 2006 revealed that PPE increased 5-fold in the post-heptavalent pneumococcal conjugate vaccine (PCV7) period (2001-2005) relative to the pre-PCV7 period (1996-2000), from 13 cases to 65. Most of this increase was associated with culture-negative empyema, which accounted for 61% of all post-2000 cases; 19% was culture-positive pneumococcal empyema. Our analysis indicates that non-PCV7 serotypes became more prevalent at our institution after introduction of the vaccine.