956. Pneumococcal Invasive Disease in Infants Younger than 60 Days in the United States in the 13-valent Pneumococcal Conjugate Vaccine Era
Session: Oral Abstract Session: Pediatric Epidemiology: Outbreaks and Surveillance
Friday, October 28, 2016: 11:00 AM
Room: 288-290

Background: The impact of PCV13 on invasive pneumococcal disease (IPD) in infants <60 days, who are too young to be immunized, is unknown. We compared the serotype (St) distribution, antibiotic susceptibility and clinical syndrome of infants <60 days with IPD 5 yrs before and 5 yrs after the introduction of PCV13.

Methods: We identified infants <60 days with IPD at 8 children’s hospitals in the US (1/1/2005 - 12/31/2015). Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Patients were divided into 3 subgroups: pre-PCV13 (2005-2009), transitional year (2010) and post-PCV13 (2011-2015). Dichotomous variables were analyzed by Χ2 test and continuous variables with non-parametric tests.

Results: During the study period, 53 of 1816 (2.9%) children with IPD were infants <60 days; 27 of 1004 (2.7%) during 2005-2009 and 20 of 644 (3.1%) during 2011-2015 (p=0.6). Four (7.5%) patients developed IPD within 24 hours of life, and 10 (18.9%) in the first 7 days. 73.6% of cases occurred in infants aged 31-59 days. Four infants were born at <37 weeks. Bacteremia without focus was the most common clinical syndrome (43.4%), followed by meningitis (32.1%), mastoiditis (11.3%) and pneumonia (9.4%). The most common presentation among infants aged ≤7 days was meningitis (70%) and among infants aged >7 days was bacteremia (48.8%).  The age distribution and clinical syndromes remained unchanged after the introduction of PCV13. Two term infants with meningitis died. Overall, the most common St was 19A (22.4%). St19A decreased from 29.6% in 2005-2009 to 17.6% in 2011-2015 (p=0.5). PCV13 Sts caused 81.5% and 58.8% of cases before and after the introduction of PCV13 (p=0.2), respectively. In 2011-2015, Sts 19A, 19F and 3 remained the most common Sts. St 7F was not identified in 2011-2015. Overall, 70% of isolates were penicillin susceptible (MIC ≤0.06). Penicillin susceptibility decreased from 85.2% in 2005-2009 to 58.8% in 2011-2015 (p=0.08).

Conclusion: After the introduction of PCV13, the number of cases of IPD in infants <60 days slightly decreased. PCV13 serotypes 19A, 19F and 3 were the most common Sts affecting this age group in 2011-2015, which contributed to the penicillin nonsusceptibility increase.

Liset Olarte, MD1, William J. Barson, MD, FPIDS2, John S. Bradley, MD, FIDSA, FPIDS3, Tina Tan, MD, FIDSA4, Philana Ling Lin, MD5, Jose R. Romero, MD6, Laurence B. Givner, MD7, Jill Hoffman, MD8, Kristina Hulten, PhD1, Edward Mason Jr, PhD1 and Sheldon L. Kaplan, MD, FIDSA1, (1)Baylor College of Medicine and Texas Children's Hospital, Houston, TX, (2)Nationwide Children's Hospital and The Ohio State University College of Medicine, Columbus, OH, (3)Rady Children's Hospital - San Diego, San Diego, CA, (4)Northwestern University Feinberg School of Medicine, Chicago, IL, (5)Children's Hospital of Pittsburgh, Pittsburgh, PA, (6)University of Arkansas for Medical Sciences, Little Rock, AR, (7)Wake Forest University School of Medicine, Winston-Salem, NC, (8)Children's Hospital, Los Angeles, Los Angeles, CA

Disclosures:

L. Olarte, None

W. J. Barson, None

J. S. Bradley, None

T. Tan, None

P. L. Lin, None

J. R. Romero, GSK: Investigator , Research grant

L. B. Givner, None

J. Hoffman, None

K. Hulten, None

E. Mason Jr, None

S. L. Kaplan, Forest Labs: Grant Investigator , Research support and Site-PI for clinical trial unrelated to presented research
Pfizer: Grant Investigator , Research grant
Cubist: Grant Investigator , Research grant and Site-PI for clinical trial unrelated to presented research

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