Dubé et al. BMC Public Health 2011, 11:128 http://www.biomedcentral.com/1471-2458/11/128 were reevaluated in the final model to check for con- founding and model fit. A probability level of p < 0.05 based on two-sided tests was considered statistically sig- nificant. The collinearity was checked and the adequacy of the model was evaluated by Hosmer and Lemeshow’s goodness of fit test. Multiple correspondence analysis (MCA) method [19] was also used as a complementary way to analyse our dataset. MCA is used to detect links between variables (including, in this study, the intention to recommend the A(H1N1) vaccine), but there is no dependent vari- able. This method is a form of principal components analysis that is appropriate for qualitative variables. MCA searches for principal components, which are new quantitative modelled variables, constructed as linear functions of the initial variables. Finding the principal components is based on the maximisation of the corre- lation ratio between the principal component and the initial variables. All principal components are mutually uncorrelated by construction. Our initial variables were all variables in the questionnaire pertaining to A(H1N1) vaccine and A(H1N1) influenza and the subset variable. Analysis was computed using the raw variables (6 degrees of answers ranging from “Strongly agree” to “Strongly disagree”). We carried out this MCA as a sen- sitivity analysis to better assess the role of the subset variable and the impact of all 6 degrees of possible answers on the Likert scale. The Statistical Analysis Sys- tems (SAS®) software (version 9.2 of the SAS system for Windows. Copyright (c) 2002-2008 by SAS Institute Inc., Cary, NC, USA) and R software (version 2.11.1) [20] with the library FactoMineR [21] were used for data analyses. Results Participation and socio-professionals characteristics Overall, 912 paediatricians have completed the question- naires: 714 completed the questionnaire before the beginning of the A(H1N1) vaccination campaign and 197 completed it after. After exclusion of physicians no longer practicing, those with incorrect addresses or those who were subspecialists, the overall participation rate was 50% (911/1832). Participation rates by country regions varied from 40.1% in Prairies to 57.7% in Que- bec. Table 1 shows respondents’ socio-professionals characteristics. No statistically significant differences were found among the characteristics of paediatricians who complete the survey before and after the beginning of A(H1N1) vaccination campaign. Knowledge, attitudes and practices regarding vaccination in general Overall, 98% of paediatricians thought that vaccines recommended by public health authorities are very Page 3 of 9 useful (97,6% before and 98,5% after; p = 0,5911), and 73% agreed or strongly agreed with the statement “it is very useful to protect children with the vaccines against seasonal influenza” (72,9% before and 73,9% after; p = 0,7855). When recommending new vaccines to their patients, 91% of paediatricians indicated that they are highly influenced by expert group recommendations (91,3% before and 90,7% after; p = 0,8152) and 90%, by professional association recommendations (90,8% before and 89,7% after; p = 0,6414). Approximately half of pae- diatricians (49%) stated that it is easy for them to advise their patients on new vaccines. No statistically signifi- cant differences were found in attitudes towards vacci- nation in general between respondents who answered before or after the beginning of A(H1N1) vaccination campaign Knowledge, attitudes and practices regarding A(H1N1) pandemic influenza and its prevention by vaccination Before the beginning of the campaign, 63% of paediatri- cians perceived A(H1N1) pandemic infection as a ser- ious disease, that would occur frequently without vaccination comparatively to more than 75% after cam- paign initiation. In addition, less respondents considered that A(H1N1) pandemic influenza was severe enough to take special precautions to prevent it before, than after the start of the vaccination campaign (73% agreed or strongly agreed before compared to 63% after, p = 0.0136) (Table 2). Before the vaccination campaign, half of respondents or less agreed or strongly agreed that the A(H1N1) vaccine was safe (50%) and effective (35%) compared to 77% and 72% after the start of the cam- paign who felt the vaccine was safe and effective (p < 0.001) (Table 2). Paediatricians’ perceived acceptability of A(H1N1) vaccine by the public remained comparable (45% before versus 41% after agreed and strongly agreed, p = 0.3608). Paediatricians’ perceived acceptability of the A(H1N1) vaccine by health professionals who adminis- tered vaccines (hereafter named “vaccine providers”) increased after the beginning of vaccination campaign (71% before versus 84% after, p < 0.001). Respondents’ intention to recommend the A(H1N1) vaccine increased from 80% before the beginning of the campaign to 92% after, including 46% and 62% of paediatricians that declared they would strongly recommend it, respectively. Globally, 40% of respondents who disagreed with the usefulness to protect children with the seasonal influ- enza vaccine did not intended to recommend A(H1N1) pandemic vaccine to their patients while 2% of physi- cians who agreed with the usefulness of the seasonal influenza vaccine did not intended to recommend the A (H1N1) pandemic vaccine (p < 0.001) (data not shown). The majority of respondents intended to get vaccinated against A(H1N1) pandemic influenza themselves (84%