AIM:To investigate the 7-valent pneumococcalconjugate vaccine(PCV7)effectiveness.METHODS:A systematic literature review of studies which evaluated the effectiveness of PCV7 vaccine was performed searching the keyword“heptavalent pneumococcal conjugate vaccine”in PubM ed and Scopus until March 16,2013.The selection of potential eligible articles was done by two researchers independently on the basis of abstract and title and only post-marketing studies were included in the systematic review.Data extraction was carried out by two researchers with respect to invasive pneumococcal diseases due to both all and vaccine serotypes in pre-vaccine and postvaccine periods in children less than 5 years.Results of studies which were considered suitable for meta-analysis were combined by means of relative risk(RR)with95%CI.Vaccine effectiveness was calculated as(1-RR)×100.Heterogeneity was assessed by I2 and a random effects model was used to combine data in the case of heterogeneity.RevM an 5 was used to pool data.RESULTS:On the whole,757 eligible papers were identified from the literature search in PubM ed and Scopus.Of them,62 were finally considered in the systematic review and 38 were included in the meta-analysis.In all post-marketing studies included in the systematic review the incidence of invasive pneumococcal diseases due to vaccine serotypes declined significantly with the exception of few studies showing stability or a slight,but not significant,increase.Furthermore most of studies highlighted also a reduction in the incidence of invasive pneumococcal diseases due to all serotypes.With regards to meta-analysis,a random effects model was used to combine data because of the high heterogeneity.Data combination showed that the effectiveness of PCV7in reducing invasive pneumococcal diseases due to vaccine serotypes and to all serotypes was 84%(95%CI:74%-90%)and 53%(95%CI:46%-59%)respectively.These results are confirmatory with respect to the efficacy of PCV7 against invasive pneumococcal diseasesdue to vaccine serotypes.CONCLUSION:PCV7 implementation determines a significant decrease of invasive pneumococcal diseases. AIM: To investigate the 7-valent pneumococcal conjugate vaccine (PCV7) effectiveness. METHODS: A systematic literature review of studies that evaluated the effectiveness of PCV7 vaccine was performed searching the keyword “heptavalent pneumococcal conjugate vaccine” in Pubmed and Scopus until March 16,2013. The selection of potential eligible articles was done by two investigators on the basis of abstract and title and only post-marketing studies were included in the systematic review. Data extraction was carried out by two researchers with respect to invasive pneumococcal diseases due to both all and vaccine serotypes in pre-vaccine and postvaccine periods in children less than 5 years. Results of studies which were considered suitable for meta-analysis were combined by means of relative risk (RR) with 95% CI. Vaccine effectiveness was calculated as (1-RR) × 100. Heterogeneity was assessed by I2 and a random effects model was used to combine data in the case of heterogeneity. RevM an 5 wa s used to pool data .RESULTS: On the whole, 757 eligible papers were identified from the literature search in PubM ed and Scopus. Of them, 62 were finally considered in the systematic review and 38 were included in the meta-analysis. all post-marketing studies included in the systematic review the incidence of invasive pneumococcal diseases due to vaccine serotypes declined significantly with the exception of few studies showing stability or a slight, but not significant, increase.Furthermore most of studies highlighted also a reduction in the incidence of invasive pneumococcal diseases due to all serotypes. Because of to meta-analysis, a random effects model was used to combine data because of the high heterogeneity. Data Assembly showed that the effectiveness of PCV7 invasive pneumococcal diseases due to vaccine serotypes and to all serotypes were 84% (95% CI: 74% -90%) and 53% (95% CI: 46% -59%) respectively.These results are confirmatory with respect to the efficacy of PCV7 against in vasive pneumococcal diseasesdue to vaccine serotypes.CONCLUSION: PCV7 implementation determines a significant decrease of invasive pneumococcal diseases.