666. Early Evidence of 13 Valent Pneumococcal Conjugate Vaccine Impact on Carriage of Vaccine Serotypes
Session: Poster Abstract Session: Pneumococcal Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
Background: The effectiveness of PCV7 has included both the direct effect of pneumococcal disease reduction in vaccinated children and an indirect benefit across all age cohorts as a result of reduction in carriage of vaccine serotypes and transmission to unvaccinated populations.  Ongoing carriage surveillance following the introduction of PCV13 is necessary to understand the likelihood that herd benefits will accrue as well as to evaluate the potential for NP replacement with non vaccine serotypes.

Methods: NP surveillance was performed in children < 60 months of age attending the primary care center (PCC) at Boston Medical Center.  NP cultures were collected after obtaining informed consent and processed by routine microbiologic methods.  Suspected isolates of Streptococcus pneumoniae (SP) were confirmed as SP and serotyped using Quellung reaction.  Demographic information was obtained both from parent interview and chart review. The results of cultures collected between 2010/2011 were compared with those from a comparable surveillance study at the PCC in 2006/2007.

Results: 925 children had NP culture performed between 11.1.2010 and 4.30.2011; SP was recovered from 212 (22.9%).  Between 2007 and 2011, in children < 12 months of age, pneumococcal carriage prevalence was comparable (21.7 per 100 vs. 23.2 per 100), however overall carriage of a PCV 13 serotypes (1, 3, 5, 6A, 7F, 19A) declined in 2011 from 7.3/100 to 1.3/ 100 [P=0.002]. In children 12 though 59 months of age, pneumococcal carriage increased in 2011 from 23.8/100 to 30.2/100 (P=0.01) but no difference in carriage of the 6 additional serotypes in PCV13 was observed (4.4/100 vs 4.9/100). A reduction in carriage prevalence of serotypes 6A and 7F (P=0.06 and 0.12 respectively) was observed in children 0 through 59 months of age but no change in carriage of 19A is evident to date.

Conclusion: In the first fall/winter season following replacement of PCV7 with PCV13 in the childhood immunization schedule, a decline in carriage prevalence for the 6 additional vaccine serotypes was observed in children < 12 months, but not in children 12 to 59 months.  A non-statistically significant decline in carriage of serotypes 6A and 7F in children 0 through 59 months, was observed.

Subject Category: P. Pediatric and perinatal infections

Katherine Hsu, MD, MPH1, Anita Loughlin, PhD1, Abbie Stevenson, BS2 and Stephen I. Pelton, MD MPH1, (1)Sect. of Pedi. ID, Boston Univ Med Ctr, Boston, MA, (2)Boston Univ Med Ctr, Boston, MA


K. Hsu, Pfizer: Grant Investigator, Research grant

A. Loughlin, None

A. Stevenson, None

S. I. Pelton, Pfizer: Scientific Advisor, Research grant

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.