Background: Although invasive pneumococcal disease (IPD) has declined following pneumococcal conjugate vaccines, both respiratory (R-IPD; e.g., pneumonias +/- empyema) and non-respiratory 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 (Figure2). By Era 2 PCV13 immunization was broadly implemented (Figure3). 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.
M. Cheung, None
A. Arrieta, Melinta Therapeutics: Investigator , Research support .