Dubé et al. BMC Public Health 2011, 11:128 http://www.biomedcentral.com/1471-2458/11/128 Table 3 Variables associated with respondents intention to recommend A(H1N1) pandemic vaccine in multivariate regression analysis (N = 709) * Adjusted OR 95% CI P value Variables Paediatricians’ intention to receive A (H1N1) themselves Belief§ that A(H1N1) vaccine will be well accepted by vaccine providers Belief§ that seasonal influenza vaccines are very useful to protect children health Belief§ that A(H1N1) pandemic influenza generate a significant economic burden in Canada Self-estimated sufficiency of knowledge on A(H1N1) vaccine Belief§ that A(H1N1) vaccine will be safe Belief§ that A(H1N1) pandemic influenza is a serious disease Belief§ that A(H1N1) pandemic influenza is a severe enough to take special precautions to prevent it Subset variable (before = 1, after = 0) 8.65 6.60 2.84 2.78 2.10 2.10 2.09 1.88 0.84 4.27-17.14 <0.0001 3.70-11.76 <0.0001 1.58-5.10 0.0005 1.51-5.08 0.0010 1.05-4.20 1.13-3.90 1.13-3.88 1.04-3.42 0.0351 0.0195 0.0189 0.0377 0.36-1.96 0.6864 * Multivariate analyses; OR = odds ratio; CI = confidence interval; 205 physicians were excluded because of missing answers (170 before and 32 after). § Strongly agree, agree. were low (maximum at 0.71 for the first principal compo- nents, and 0.57 for the second principal component). It showed that responses were homogeneous among respondents. More precisely, results showed that we could group our respondents by negative levels rather than positive levels of their answers: the levels “strongly disagree” and “disagree” were the most discriminatory levels. Before and after the onset of the vaccination cam- paign, the modelled principal component had the respondents’ intention to recommend A(H1N1) pan- demic vaccine as principal contributor (weight for the “strongly disagree” level: 4.14). Then we found respon- dent’s intention to receive A(H1N1) pandemic vaccine (weight for the ‘no’ level: 3.45), and “belief that seasonal influenza vaccines are very useful to protect children health” (weight for the “strongly disagree” level: 3.44). Mean of weight for all other variables is 0.87, including the subset variable which was the less correlated variable (variable S on figure 1) with first and second principal components. Discussion To our knowledge, this is the first study that measured changes in physicians’ KAP regarding A(H1N1) pan- demic influenza and its prevention by vaccination before and after the approval of the vaccine and start of the vaccination campaign. Previous studies among health Page 6 of 9 care workers assessed acceptability of the A(H1N1) vac- cine before its official approval and program implemen- tation or used hypothetical pandemic vaccination scenarios [18,22-26]. In these studies, intention to be vaccinated against A(H1N1) pandemic influenza varied from 48% to 80% among healthcare workers, compara- tively to 84% of paediatricians surveyed before the beginning of the vaccination campaign in our study. Similarly to our results, a study done in Mexico reported that 72% of healthcare workers would recom- mend the vaccine to their patients, and they were more likely to do so when they had the intention to get vacci- nated themselves [25]. Results of this national survey among paediatricians indicated an important increase in paediatricians percep- tions of the burden of A(H1N1) pandemic influenza and support for A(H1N1) vaccination after the beginning of the vaccination campaign. Respondents’ endorsement of almost all items regarding A(H1N1) pandemic influenza and its prevention by vaccination increased after the start of the vaccination campaign. This is not surprising given the fact that the first A(H1N1) vaccine available in Canada used a novel adjuvant (AS03) for which limited information regarding the safety and immunogenicity was available. The proportion of physicians who reported they had received sufficient information about A(H1N1) vaccine also increased by 42% after the start of the vaccination campaign. This increase may be attri- butable to the important educational efforts done at the beginning of the vaccination campaign along with the official recommendations by expert groups and profes- sional associations that were released in early November [27-29]. Health professionals’ knowledge about vaccines has been previously shown as a main determinant associated with their own vaccine uptake and their intention to recommend the vaccine to their patients [30,31]. The association between physicians own vaccination beha- viours and their recommendations to their patients was previously established [12,32-35]. It appears to hold true in a pandemic context, as shown by our results and those previously reported in Mexico [25]. Our results highlight the positive change in paediatri- cians’ knowledge and level of support of the A(H1N1) vaccines throughout the pandemic vaccination cam- paign. This change may be attributable to increased education efforts and the very rare vaccine associated adverse events [36], but may also reflect the intense media attention focused on the vaccination campaign. A recent UK study has shown that healthcare workers were more willing to accept stockpiled H5N1 vaccine during a period of high media coverage of a H5N1 out- break in a poultry farm than 6 months after (63.4% vs. 51.9%, p = 0.009) [18]. The increased exposure of