A Retrospective Study of the Impact of Pneumococcal Conjugate Vaccine-13 Immunization in a Northern Israel Hospital.

BACKGROUND

The introduction of pneumococcal conjugate vaccine-13 (PCV-13) has reduced the burden of invasive pneumococcal disease.

OBJECTIVES

To characterize true positive blood cultures of children who presented to our hospital following implementation of the PCV-13 vaccine.

METHODS

A retrospective study was conducted on positive blood cultures of children presenting with fever from 2010-2017. Subjects were divided into two age groups: a younger group 3-36 months and an older group 3-18 years. Patients were classified as either having or not having a focus of infection at the time of their bacteremia. Pneumococcal isolates were typed at Israel's Streptococcal Reference Laboratory.

RESULTS

The samples included 94 true positive blood cultures. Focal infection with concomitant bacteremia was more common than bacteremia without a focus both overall: 67/94 (71%) vs. 27/94 (28.7%), P <0.001 as well as in the two groups: 32/48 (66%) vs. 16/48 (33%), P = 0.02 in the younger group and 35/46 (76%) vs. 11/46 (24%), P = 0.001 in the older group. Streptococcus pneumoniae was the most common pathogen overall, 27/94 (29%), and in the younger group, 21/48 (44%), but rare in the older group, 6/46 (13%). In the latter, Brucella species predominated, 12/46 (26%), along with Staphylococcus aureus 12/46 (26%).

CONCLUSIONS

Our findings are consistent with other studies reporting decreased pneumococcal bacteremia, bacteremia primarily accompanying focal infection, and changing etiological agents among PCV-13-vaccinated children. Brucella species was prominent in older children with osteoarticular infections. Ongoing surveillance is warranted to better understand the implications of PCV-13.