Routine use of the 13-valent pneumococcal conjugate vaccine (PCV13) reduced the incidence of Streptococcus pneumoniae bacteremia by 95% from a time period before to a time period after the vaccine was implemented, based on a review of more than 57,000 blood cultures from children aged 3-36 months.
Kaiser Permanente implemented universal immunization with PCV13 in June 2010. “Initial trends through 2012 demonstrated continued decline in pneumococcal infections, with the biggest impact in children less than 5 years old,” wrote Tara Greenhow, MD, of Kaiser Permanente Northern California, San Francisco, and her colleagues.
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Overall, the incidence of S. pneumoniae bacteremia declined from 74.5 per 100,000 children during the period before PCV7 (1998-1999) to 3.5 per 100,000 children during a period after routine use of PCV13 (2013-2014). The annual number of bacteremia cases from any cause dropped by 78% between these two time periods.
As bacteremia caused by pneumococci decreased, 77% of cases in the post-PCV13 time period were caused by Escherichia coli, Salmonella spp., and Staphylococcus aureus. “A total of 76% of bacteremia occurred with a source, including 34% urinary tract infections, 17% gastroenteritis, 8% pneumonias, 8% osteomyelitis, 6% skin and soft tissue infections, and 3% other,” Dr. Greenhow and her associates reported.
The large population of the Kaiser Permanente system supports the accuracy of the now rare incidence of bacteremia in young children, the researchers noted. However, “because bacteremia in the post-PCV13 era is more likely to occur with a source, a focused examination should be performed and appropriate studies should be obtained at the time of a blood culture collection,” they said.