LAUSR

BACKGROUND Pneumococcal conjugate vaccines (PCVs) have decreased pneumonia in children. Colombia introduced mass vaccination with PCV10 in 2012. METHODS Cases of pneumococcal pneumonia from 10 hospitals were included. Two periods were compared: pre-PCV10: 2008-2011 and post-PCV10: 2014-2019. The objective was to compare epidemiological and clinical characteristics before and after PCV10 vaccination. RESULTS A total of 370 cases were included. Serotypes 1 (15, 11.2%) and 14 (33, 24.6%) were the most frequent in the pre-PCV10 period, with only 4 (3%) cases of serotype 19A and 1 case (0.7%) serotype 3. From the pre-PCV10 period to the post-PCV10 period, cases of serotypes 1 (6, 3.1%) and 14 (1, 7.8%) decreased, while cases of serotypes 19A (58, 30.2%), serotype 3 (32, 16.7%) and 6A (7, 3.6%) increased (p < 0.001); complicated pneumonia (CP) increased significantly (13.4% to 31.8%) (p < 0.001); hospitalizations increased from 8 (5.5-15) to 12 (7-22) days (p < 0.001); and the frequency of PICU admission increased from 32.8% to 51.6% (p = 0.001). The use of ampicillin-sulbactam (0.7% to 24%) and ceftriaxone/clindamycin (0.7% to 5.7%) increased in the post-PCV10 period. The duration of empirical antibiotic treatment was 7 (4-11) days in the pre-PCV10 period and increased to 10 (6-17) days (p < 0.001) in the post-PCV10 period. Lethality showed a slight nonsignificant increase (7.5% vs. 9.9%; p = 0.57) in the post-PCV10 period. CONCLUSIONS PCV10 significantly decreased cases of serotypes 1 and 14, with an increase in cases of serotypes 19A, 3 and 6A, which were the predominant serotypes and had greater severity (e.g., admission to the PICU, CP and more resistance, with an increase in the use of broad-spectrum antibiotics and longer hospitalization) and subsequently included in PCV13. Current data support national and regional evidence on the importance of replacing PCV10 with a higher valence that includes 19A, such as PCV13, with the aim of reducing circulation, particularly of this serotype.