Study Examines How the Pneumococcal Vaccine Has Affected Rates of Bacteremia

Since the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), rates of bacteremia have been reduced significantly in otherwise healthy toddlers, according to a new study.

The retrospective review included electronic medical records and 57,733 blood cultures from children 3 to 36 months enrolled in Kaiser Permanente in Northern California from September 1, 1998 to August 31, 2014. Researchers compared incidence of bacteremia from before the 7-valent pneumococcal conjugate vaccine (PCV7) was introduced, after PCV7 but before PCV13, and after PCV13.
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According to the results, routine immunization of children with the pneumococcal conjugate vaccine reduced Streptococcus pneumoniae bacteremia by 95.3%, decreasing incidents from 74.5 per 100,000 children before PCV7 to 10 per 100,000 children after PCV7 and to 3.5 per 100,000 children after PCV13.

Conversely, Escherichia coli, Salmonella spp, and Staphylococcus aureus rates increased and caused 77% of bacteremia as pneumococcal rates decreased.

“In the United States, routine immunizations have made bacteremia in the previously healthy toddler a rare event. As the incidence of pneumococcal bacteremia has decreased, E coli, Salmonella spp, and S aureus have increased in relative importance,” the researchers concluded. “New guidelines are needed to approach the previously healthy febrile toddler in the outpatient setting.”

—Melissa Weiss

Reference:

Greenhow TL, Hung YY, and Herz A. Bacteremia in children 3 to 26 months old after introduction of conjugated pneumococcal vaccines [published online March 31, 2017]. Pediatrics. doi:10.1542/peds.2016-2098.