Objective To measure the effectiveness of pneumococcal conjugated vaccine (PCV13) against Community Acquired Pneumonia (CAP) and invasive pneumococcal disease, 2 years after the vaccine (2+1) was included into the National Immunization Program of Argentina, and to describe variables associated with bacterial pneumonia and hospitalization. Methods This was a prospective, population-based surveillance study of CAP incidence (ambulatory and hospitalized) among children less than 5 years of age in the Department of Concordia (Entre Rios, Argentina) from April 2014 – March 2016. The diagnosis of probable bacterial pneumonia (PBP) was determined following the standardized WHO protocol. Incidence during the post-vaccine introduction period was compared with the results from a previous study that used similar methodology for the pre-PCV13 introduction period from 2002 – 2005. Results During the study period, 330 patients had a clinical diagnosis of CAP, of which 92 were PBP (6 with pleural effusion). S. pneumoniae was not isolated from any sample. No factors associated with PBP were found in multivariable analysis. The decrease in PBP and pleural effusion was significant in relation to the previous study: 63% (P < 0.0001) and 80.9% (P < 0.003), respectively. PCV13 uptake was 97.3% for the 1st dose and 84.8% for the booster dose. Conclusions PCV13 was effective to reduce incidence of consolidated pneumonia and pleural effusion, among children less than 5 years of age in Concordia, Argentina. Vaccination is a very effective public health strategy for reducing vaccine preventable diseases, with impact on burden of disease and hospitalization.

BackgroundIn January 2012, Argentine introduced PCV-13 to the National Immunization Program. We performed an epidemiological study in order to describe consolidated pneumonia and pneumococcal disease incidence following PCV-13 routine vaccination.MethodsBetween April2014-March2016, a population-based surveillance study was carried out in Concordia. Clinical data, vaccination status and digital chest X-rays were recorded from children < 5 years old with pneumonia and pleural effusion. A pediatrician and a radiologist interpreted the images independently. A second reference radiologist arbitrated when discordances occurred. Bacterial etiology was investigated in blood and/or in pleural fluid. Probably bacterial pneumonia (PBP) was determined following WHO protocol. Results were compared with previous data (2002–2005) from the pre-PCV-13 vaccination era. Variables associated to consolidated pneumonia were evaluated by multivariate analysis using logistic regressionResults330 patients under 5 years old with pneumonia were assisted during the study period. Of these, 92 (27.9%-IC95% 23.2–33.1) were classified as PBP. Annual incidence rate, in pre and post vaccination period and impact of vaccination are described in table 1. Incidence of pneumococcal disease could not be estimated as pneumococcal isolation was negative in all cases.Multivariate analysis of post-PCV-13 vaccination era showed that incidence of consolidated pneumonia was significantly higher in hospitalized toddlers than outpatients OR: 2,97 (1,65–5,38). Table 1: PBP incidence (*100.000) by study period. Vaccination impactFinal ClassificationPre-vacccination periodPost vaccination periodImpact of 
vaccination N PopulationIncidencenPopulationIncidenceIncidence Rate ratio (IC95%)Decrease P 
valueConsolidated pneumonia38718.053714,68615.493283.92.5 (1.8–3.6)60.2%<0.001Pneumonia with pleural effusion7218.053132.9615.49319.46.7 (2.1–35.6)85.4%0.004PBP (total)45918.053847.59215.493296.92.8 (2–4)64.9%<0.001ConclusionA significant decline in consolidated pneumonia and pleural effusion incidence in <5 year old children was evidenced in Concordia after the introduction of PCV13 into national immunization program.Disclosures All authors: No reported disclosures.