Direct meta-analyses comparing the immunogenicity (rates of seroconversion *) of adjuvanted versus non-adjuvanted H1N1 influenza vaccines.

Only randomized trials were included. All doses are in µg. N = total number of subject analyzed; (ref) = References to included studies; RR = Random-effect risk ratio; CI = Confidence Intervals; Ad = Adjuvant.1Adults = from 18 to 64 years;2Elderly = from 65 years;3Adolescents = from 10 to 17 years;4Children = from 6 months to 9 years (see Table S1 for several exceptions).*Seroconversion = subjects with a pre-vaccination hemagglutinination-inhibition antibody titer = 1∶40, or a pre-vaccination titer > = 1∶10 and an increase in the titer by a factor of four or more after vaccination.**The total sample of overall meta-analyses may be lower (higher) than the sum of stratified meta-analyses because some arms had to be split to be included in more than a stratified meta-analysis (some arms were different from the main comparisons shown in the Table); in any case, no subject was counted twice. Al = Only aluminum adjuvants; Sq = Only squalene-based (oil-in-water) adjuvants.