Pneumococcal Pneumonia Requiring Hospitalization in US Children in the 13-Valent Pneumococcal Conjugate Vaccine Era.

BACKGROUND.: The impact of PCV13 on a number of clinical aspects of pneumococcal pneumonia (PP) in children has not been reported. We compared the serotype distribution, antibiotic susceptibility, and outcomes of children with PP 4 years before and 4 years after the introduction of PCV13. METHODS.: We identified patients ≤18 years with PP at 8 children's hospitals in the United States (2006-2014). Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Clinical and laboratory data were collected retrospectively. Annual pneumococcal pneumonia hospitalization rates per 100 000 admissions with 95% confidence intervals were calculated. Dichotomous variables were analyzed by χ2 test and continuous variables with Mann-Whitney U test. RESULTS.: A total of 377 patients with PP requiring hospitalization were identified. Hospitalization rates of PP decreased from 53.6 to 23.3 per 100000 admissions post PCV13 (P < .0001). Complicated PP rates also decreased (P < .0001). Need for intensive care, mechanical ventilation, and invasive procedure remained unchanged after the introduction of PCV13. Comorbidities were more common among children with uncomplicated than complicated pneumonia (52.2% vs. 22.5%, P < .001). Overall, PCV13 serotypes 19A, 3, 7F, and 1 caused 80% of PP. Hospitalization rates of PCV13 serotype pneumonia decreased from 47.2 to 15.7 per 100000 admissions post PCV13. In 2014, the most common serotypes were 3, 19A and 35B. CONCLUSIONS.: PP requiring hospitalization significantly decreased in children after PCV13 introduction. Complicated PP rates decreased steadily in 2011-2014. PCV13 serotypes 19A and 3 were still responsible for half of the cases of PP in 2011-2014.