Changes in empyema among U.S. children in the pneumococcal conjugate vaccine era. Issue 50 (7th December 2016)

• Record Type: Journal Article
• Authors: Wiese, Andrew D.; Griffin, Marie R.; Zhu, Yuwei; Mitchel, Edward F.; Grijalva, Carlos G.
• Is Part Of: Vaccine. Volume 34:Issue 50(2016)
• Page Start: 6243
• Page End: 6249
• Publication Date: 2016-12-07
• Subjects: U.S. United States -- PCV7 7-valent pneumococcal conjugate vaccine -- PCV13 13-valent pneumococcal conjugate vaccine -- IPD invasive pneumococcal disease -- PCV pneumococcal conjugate vaccine -- NIS Nationwide Inpatient Sample -- ICD9-CM International Classification of Diseases, 9th revision-Clinical Modification -- RR relative rate -- CI confidence interval -- HCUP Healthcare Cost and Utilization Project; Parapneumonic empyema -- Pneumococcal conjugate vaccine -- Invasive pneumococcal disease -- Epidemiology; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2016.10.062
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: Parapneumonic empyema started increasing among U.S. children before PCV7 introduction in 2000, and continued afterwards. PCV13 introduction was associated with a reduction in parapneumonic empyema among U.S. children. The empyema rate reached a historical low among children <2 years after PCV13 introduction. Abstract: Background: Parapneumonic empyema, a serious complication of pneumonia, started increasing among U.S. children before the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000, and continued afterwards. This increase was due in part to pneumococcal serotypes not included in PCV7 that were included in the new 13-valent (PCV13) vaccine introduced in 2010. We assessed changes in the incidence of empyema hospitalizations among U.S. children after PCV13 introduction. Methods: We calculated annualized empyema hospitalization rates among U.S. children <18 years using Nationwide Inpatient Sample and Census data (1997–2013) for four periods based on PCV7 and PCV13 introductions. Relative rates (RR) and 95% confidence intervals (CI) were calculated by age group and sex, comparing PCV7 [early-PCV7 (2001–2005) and late-PCV7 (2006–2009)] and PCV13 (2011–2013) periods with the pre-PCV7 period (1997–1999). Secondary analyses examined changes in pneumococcal, streptococcal, staphylococcal and unspecified empyema. Results: Among children <18 years of age, annualized empyema hospitalization rates peaked at 3.6 per 100, 000 in the late-PCV7 period compared with 2.1 per 100, 000 in the pre-PCV7 period [RR: 1.70 (95% CI: 1.11–2.60)]. However, annualized rates in the post-PCV13 period declined to 2.0 per 100, 000, similar to rates in the pre-PCV7 period. Empyema rates among children <2 years were lower in the post-PCV13 period compared to the pre-PCV7 period [RR: 0.77 (95% CI: 0.61–0.96)], but rates in the two periods among children 2–4 and 5–17 years were similar. Most empyema were of unspecified etiology. Pneumococcal and unspecified empyema declined after PCV13 introduction. Conclusions: Although empyema hospitalization rates among U.S. children peaked after PCV7 introduction, rates decreased substantially following the introduction of PCV13.