Impacts on influenza A(H1N1)pdm09 infection from cross-protection of seasonal trivalent influenza vaccines and A(H1N1)pdm09 vaccines: systematic review and meta-analyses.

摘要: Cross-protection by seasonal trivalent influenza vaccines (TIVs) against pandemic A H1N1 2009 (now known as A[H1N1]pdm09) infection is controversial; and the vaccine effectiveness (VE) of A(H1N1)pdm09 has important health-policy implications. Systematic reviews meta-analyses are needed to assess impacts both TIVs A(H1N1)pdm09.We did a systematic literature search identify observational and/or interventional studies reporting cross-protection TIV VE from when started (2009) until July 2011. The fulfilling inclusion criteria were meta-analysed. For VE, respectively, we stratified type, study design endpoint. Seventeen (104,781 subjects) 10 (2,906,860 subjects), reported vaccines; six (17,229 on both. Thirteen (95,903 cross-protection, eight (859,461 five (9,643 meta-analysed revealed: (1) for confirmed illness was 19% (95% confident interval=13-42%) based 13 case-control with notable heterogeneity. higher 34% (9-52%) found in sensitivity analysis (excluding moderate/high risk bias). Further exclusion that recruited early (when non-recipients more likely have had non-pandemic may been cross-protective) dramatically reduced One RCT 38% (19-53%) illness. 50% (40-59%) hospitalisation. (2) 86% (73-93%) 11 79% (22-94%) two cohort studies; medically-attended ILI 32% (8-50%) one study. provided moderate laboratory-confirmed (based low bias RCT) also finding increased limited cases pandemic. highly effective Although less than direct effect strain-specific vaccination A(H1N1)pdm09, generally beneficial before available.