Background: The epidemiology of invasive pneumococcal disease (IPD) in US children changed after licensure of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000. IPD decreased after introduction of PCV7 but parapneumonic empyema (PPE) increased. Introduction of PCV13 in the US in 2010 has further reduced IPD but its impact on PPE is unknown.
Methods: We identified Utah children <18 years hospitalized in an Intermountain Healthcare (IH) facility from 1997-2014 with an International Classification of Diseases, 9th Revision (ICD-9) PPE diagnosis code and chest tube drainage procedure code. Incidence rates were calculated per 100,000 admissions. We calculated national rates by applying the same criteria to the Kids' Inpatient Database (KID). We compared rates in the pre-PCV7 (1997-2000), PCV7 (2001-2010) and PCV13 (2011-2014) eras. Cases of culture-confirmed PPE/year and pneumococcal serotypes in Utah children were also reviewed.
Results: In Utah, the incidence of pediatric PPE increased during the PCV7 era from 73 to 127/100,000 admissions (+73%; 95% CI: 30-125%) (Table). National data revealed a similar proportional, but smaller absolute, increase (54 to 92/100,000 [+70%; 95% CI: 63-76%]). After introduction of PCV13, PPE admissions declined to rates comparable to the pre-PCV7 era. Among Utah children with culture-confirmed PPE, pneumococcal PPE was most common. In the PCV7 era, culture-confirmed PPE cases increased from 5.3/year to 10/year (p=0.02). This change was primarily due to increases in PPE caused by the additional 6 serotypes contained in PCV13 (2.5/year to 8.1/year; p=0.001). After the introduction of PCV13, culture-confirmed PPE declined to 4/year concordant with a decline in PPE due to the six additional serotypes from 8.1 to 3.5/year (p=0.002). The incidence of PPE due to non PCV13 serotypes, Staphylococcus aureus and Streptococcus pyogenes did not change over the study period.
Conclusion: The introduction of PCVs in the US was associated with significant changes in the epidemiology of PPE. After introduction of PCV7, rates of PPE increased associated with increases in specific serotypes. Introduction of PCV13 has so far been associated with a marked decrease in the incidence of PPE. Ongoing surveillance should focus on the impact of PCVs on serotype and disease patterns.
C. Stockmann, None
A. J. Blaschke, BioFire Diagnostics, LLC: Collaborator , Consultant and Scientific Advisor , Consulting fee , Licensing agreement or royalty and Research support
bioMerieux, Inc: Collaborator , Investigator and Scientific Advisor , Consulting fee and Research support
Merck: Investigator , Research grant
A. L. Hersh, Pfizer: Grant Investigator , Grant recipient and Research grant
E. Thorell, None
S. K. Sanderson, None
P. Rosen, None
E. K. Korgenski, None
J. A. Daly, None
C. L. Byington, None