Burden of all-cause and organism-specific parapneumonic empyema hospitalization rates prior to the SARS-CoV-2 pandemic in the United States.

ABSTRACT

BACKGROUND AND AIMS: Parapneumonic empyema, a severe pneumonia complication, decreased shortly after 13-valent pneumococcal conjugate vaccine (PCV13) introduction in US children, though the long-term impact remains poorly described. It is also unclear whether PCV13 introduction in 2010 or the 2014 US recommendation for PCV13 use in older adults was associated with declines in empyema among adults. We examined overall and organism-specific parapneumonic empyema rates among US children and adults from 2006 to 2019, prior to the SARS-CoV-2 pandemic and the updated recommendations for PCV15 and PCV20 in the US. METHODS: We used the National Inpatient Sample and US Census Data to calculate national annual all-cause and pneumococcal empyema hospitalization rates by age group (2006-2019). We examined rates during the late-PCV13 era (October 2015-2019) after transition to ICD10 codes compared to rates in the late-PCV7 (2006-2009) and early-PCV13 era (2011-September 2015). We also examined the rate of empyema with thoracentesis-related procedures and according to the causative organism type. RESULTS: Compared to the late-PCV7 era, all-cause empyema hospitalization rates were lower among child age groups (<1, 1, 2-4 and 5-17 years) in the late-PCV13 era. In contrast, among most adult age groups (18-34, 50-64, 65+ years), all-cause empyema rates were higher in the late-PCV13 era compared to the late-PCV7 era. CONCLUSION: Early declines in all-cause empyema-related hospitalizations observed right after PCV13 introduction among children in 2010 were sustained through 2019, though rates did not decline among adults.