1432. County-Wide Pediatric IPD Experience Following Prevnar 13 Implementation

Background Although invasive pneumococcal disease (IPD) has declined following pneumococcal conjugate vaccines, both respiratory (R-IPD; e.g., pneumonias +/− empyema) and nonrespiratory IPD (NR-IPD) remain concerning. We evaluate 13-valent pneumococcal conjugate vaccine (PCV13) impact on county-wide IPD, serotypes involved and patients affected since its 2010 introduction. Methods Prospective analysis of culture confirmed pediatric IPD was conducted in Orange County, CA following PCV13 vaccine implementation comparing 2010–2013 (transition; Era 1) to 2014–2017 (full implementation; Era 2). We reviewed age, ethnicity, health status, immunizations, immune work up, site of infection, and serotype distribution. Results There were 135 IPD cases (78[58%] male; 63[47%] Hispanic, 38[28%] White, 14[10%] Asian, 9[7%] other and 11[8%] unknown). IPD decreased by 37.3% (Era 1 = 83 cases vs. Era 2 = 52). R-IPD (41.5%) and NR-IPD (58.5%) exhibited a similar decrease. Serotype was known for 116 (86%) cases. Overall PCV13 serotype incidence rate (IR) per 100,000 population decreased by 44.7%; of note non-PCV13 decreased by 14.8%. The largest change was seen in PCV13 serotype NR-IPD (−60%) (Figure 1). As a percentage of PCV13 serotypes, 19A and 3 increased from 32 and 21% to 46% (+44%) and 27% (+29%), respectively. Meanwhile, 7F decreased from 36 to 7% (−81%). R-IPD due to PCV13 serotype in children <5 years old did not decrease during the study (Figure 2). By Era 2 PCV13 immunization was broadly implemented (Figure 3). Despite being fully immunized, 12 patients (5[42%] male; 7[58%] White, 4[33%] Asian, 1[8%] other) developed PCV13 serotype IPD. The majority (10/12) were previously healthy, with R-IPD (83%) and affected by serotypes 19A (58%) or 3 (25%). No immune deficiency was identified among these subjects. Conclusion Pediatric IPD continues to decrease post PCV13 implementation, most notably due to a decrease in PCV13 serotype NR-IPD and disappearance of 7F. We did not see an increase in non-PCV13 IPD. Serotypes 19A and 3 remain a significant proportion of a lower number of cases. Children <5 remain at highest risk for IPD, particularly R-IPD. A notable proportion of PCV13 serotype R-IPD occurred in fully immunized and previously healthy children. Disclosures A. Arrieta, Melinta Therapeutics: Investigator, Research support.