Rotavirus vaccine effectiveness in Latin American and Caribbean countries: A systematic review and meta-analysis.

Introduction: There are two group A rotavirus (RVA) vaccines available worldwide since 2006: monovalent (Rotarix(®), RV1) and pentavalent (RotaTeq(®), RV5). Currently, 16 countries and 1 territory in Latin America and the Caribbean (LAC) have introduced RVA vaccines and since their introduction several impact and effectiveness studies have been conducted in different countries. The purpose of this study was to assess RVA vaccine effectiveness in LAC countries.

Methodology: We conducted a systematic review and meta-analysis of studies in children under-five who were admitted with laboratory-confirmed RVA diarrhea. We searched Medline, WOS, LILACS, Scopus, and other sources from 2006 to October 2013. Two independent evaluators identified the studies that met predefined selection criteria and extracted relevant information according to a protocol. Pooled estimates were obtained with fixed and random-effects models and stratified according to selected effect modifiers.

Results: Of the 806 articles meeting the initial criteria, 8 case-control studies which involved 27,713 participants (6265 cases and 21,448 controls) were included in the final analyses. The pooled estimates were calculated using different types of controls, leading to different degrees of effectiveness. The effectiveness of two doses of RV1 against rotavirus-related hospitalizations ranged from 63.5% (95% CI: 39.2-78.0) to 72.2% (95%CI: 60.9-80.2). Effectiveness ranged from 75.4% (95%CI: 64.6-82.9) to 81.8% (CI 95%:72.3-88.1) among infants <12 months for RV1, and from 56.5% (95%CI: 26.2-74.3) to 66.4% (95%CI: 54.1-75.5) for infants >12 months. The RV5 effectiveness for diarrhea with a Vesikari score >11 in infants 6 to 11 months old ranged from 76.1% (95%CI: 57.6-86.6) to 88.8% (95%CI: 78.3-94.3). Also, it showed 63.5% (95%CI: 29.4-82.6) of effectiveness against G2P [4].

Conclusion: RVA vaccines consistently showed protection against diarrhea-related hospitalizations in LAC. Results were more robust for RV1. Effectiveness was shown with different types of controls, but appeared somewhat higher with community controls. Effectiveness was higher among infants <12 months and lower in older children.