Figure 1.

Correlations' graph between variables and the first and second principal components. Total percentage of the variability explained by first and second principal components was 13.6%. Variables almost uncorrelated with first and second principal components aren't represented on the graph, except subset variable (S). The variables: B, C, F, G, J contributed more to first and second principal components than others. - J: Respondent's intention to recommend A(H1N1) pandemic vaccine to their patients - G: "Belief that A(H1N1) vaccine will be effective" - F: "Belief that A(H1N1) vaccine will be safe" - C: "Belief that A(H1N1) pandemic influenza is a serious disease" - B: "Belief that seasonal influenza vaccines are very useful to protect children health" All variables, including variables almost uncorrelated with first and second principal component, are listed in an additional file (see Additional File 1).