Overall difference
In the control group, the average VI score, i.e. intention to vaccinate one’s infant at 2 months of age, did not increase significantly: from 8.7 to 8.8/10 (p = 0.28). In contrast, the VI score did increase in the MI group: from 8.3 to 9.0/10 (+8.5%, p < 0.0001). The D-I-D effect between MI and control groups was estimated at +0.6 point for the VI score (p = 0.005); adding covariables to the overall model produced the same results (see 