775. Streptococcus pneumoniae nasopharyngeal carriage rates, serotype distribution and vaccine effectiveness in vaccinated and non-vaccinated healthy children in Guatemala City.
Session: Poster Abstract Session: Vaccines: Pneumococcal
Thursday, October 27, 2016
Room: Poster Hall
  • POSTER IDWEEK 2016 MELGAR.pdf (614.3 kB)
  • Background: Streptococcus pneumoniae(Spn) vaccines have a high efficacy rate, but with variations according to different settings. Colonization has been postulated as a surrogate for vaccine efficacy. We looked for Spn nasopharyngeal carriage in vaccinated and non vaccinated healthy children under 5 years of age, from public and private clinics, before conjugated pneumococcal conjugated vaccine (PCV) introduction in national immunization program.

    Methods: Study was approved by local ethics committee, informed consent was obtained for all subjects. Healthy 2- 59 months children, with no recent history of antibiotic use were included, from one public and two private well-child clinics in Guatemala City. Conjugated pneumococcal vaccine was available at the time of study only in private practice. A single nasopharyngeal swab was performed to all subjects. Nasopharyngeal carriage rates, serotype distribution and vaccine effectiveness for preventing colonization were calculated.

    Results: 500 nasopharyngeal swabs where performed from November 2012 to January 2013. Colonization rate was 32%, 40.3% in the public and 18.5% in the private clinic. Overall vaccine effectiveness for preventing colonization (1-Odds ratio) was 72% for at least one dose of any conjugated vaccine, 74% with at least two doses, 80% with at least 3 doses and 100% with four doses. Serotyping was performed in 134 of 158 positive samples. Of the serotypes found, 43% (57/158) are included in PCV 7 valent vaccine, 44% (59/158) in PCV 10 valent, 50% (68/158) in PCV 13 valent vaccine, and in 71% (96/158) in pneumococcal polysaccharide 23 valent vaccine. Serotype specific colonization prevention was 100% for most vaccine related serotypes, with exception of serotype 6B, prevented in 95% (22/23) and 98% (83/84) for PCV7 and PCV13 respectively; and 19F that was prevented 96% (81/84) for PCV13. Serotype 15B was prevented 75% with PPSV23.

    Conclusion: In our study, high vaccine effectiveness for preventing colonization was found, which could predict a good vaccine performance in our setting.

    Mario Melgar, MD, 9a Avenida 8-00 Zona 11, Department of Pediatrics, Hospital Roosevelt, Guatemala, Guatemala, Isabel Perez, MD, Multipedia, Guatemala, Guatemala, Rene Ordoñez, MD, Private practice, Guatemala, Guatemala, Irwin Paniagua, MD, Pediatrics, Department of Pediatrics, Hospital Roosevelt, Guatemala, Guatemala and Claudia Vargas, Lic, Carelab, Guatemala, Guatemala


    M. Melgar, Pfizer: Grant Investigator , Grant recipient

    I. Perez, None

    R. Ordoñez, None

    I. Paniagua, None

    C. Vargas, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.