LAUSR

Abstract Background In 2012 the 13-valent conjugated pneumococcal vaccine (PCV-13) was introduced in the National Immunization Program. We performed an epidemiological study to describe SPN nasopharyngeal carriage prevalence. Methods Between June to September 2015 it was performed a cross-sectional study among children <3 years old, attending day care centers. Nasopharyngeal samples were collected from children at public and private centers from 5 cities of Argentina (Salta (North West), Trelew (South), Rosario (Centre), Buenos Aires (Capital city) and Posadas (North East)). Samples were analyzed at references hospitals of each city and isolates were submitted to the INEI “Dr. Carlos G. Malbrán “, for confirming and serotyping. We considered completed schedule 3 doses of PCV13, administrated14 days prior to enrollment. Results We included 359 toddlers, 61,6% (IC95% 56,3–66,6) were SPN carriers. Median age was 24 months, without significative difference in carriage status. Multivariate analysis showed that independently of age, sex and socioeconomic level, variables associated with carriage were: · City: Taking Salta as reference (less carriage prevalence), Rosario and Posadas were statistically associated with higher prevalence rates: OR: 3,1 (IC95% 1,3–7,1) y OR: 2,8 (IC96% 1,2–6,3) respectively · Children attending to public day care centers had higher carriage rates than those attending private ones: OR: 1,9 (IC95% 1,06–3,4) · Children sharing bedroom with 3 or more persons, were associated to mayor risk or carriage: OR: 1,7 (IC95% 1,03–2,7) We found 46 serotypes in the 221 isolates. (2 couldn’t be serotyped), 90,9% (IC95% 86,3–94,3) were non PCV 13 serotypes (most frequent were 15B, 23B and 11A). Only 7 of 46 were PCV13 serotypes. (Graphic 1) Of the 20 toddlers with PCV13 serotypes, 16 were completely vaccinated Graphic 1: S pneumoniae serotype distribution. N = 221 Conclusion Nasopharyngeal carriage of SPN was high in children < 3 years old attending day care centers. Most isolates were Non PCV13 serotypes. The independent predictors for higher prevalence rates were: 1- Children living in the north east and Centre of the country. 2- Those attending public day care centers and 3- Those with 3 or more persons per room. Disclosures All authors: No reported disclosures.