Impact of a vaccination promotion intervention using motivational interview techniques on long-term vaccine coverage: the PromoVac strategy

Abstract

Background: Delayed vaccinations at 2, 4, and 6 months are associated with a higher probability of delayed age-appropriate vaccination during childhood. This study aimed to assess the effectiveness of an information session on immunization during infancy. Methods: An individual educational information session with motivational interview techniques for immunization of infants was conducted (experimental group) or not conducted (control group) during postpartum stay in a quasi-experimental cohort study. Immunization data were collected from the Eastern Townships Public Health registry at 3, 5, 7, 13, 19, and 24 months of age. Logistic regressions with repeated measures were performed to assess the intervention’s impact. Relative risks (RR) were estimated. A multivariate model was obtained adjusted for confounding factors. Results: The experimental and control groups included 1140 and 1249 families, respectively. In per protocol analysis, a significant increase in VC of 3.2, 4.9, 7.3, 6.7, 10.6, and 5.1% was observed at 3, 5, 7, 13, 19, and 24 months. Children from experimental group had 9% more chance at a complete vaccination status between 3 and 24 months compared to children from control group (RR (95% CI): 1.09 (1.05-1.13), p < .001). Children with complete vaccination status at 3 months were more likely to have a complete vaccination status at 24 months (82.3 vs. 48.1%, RR (95% CI): 2.72 (2.28-3.24), p < .001). After adjustment, the estimated RR of the intervention’s impact was 1.05 (1.02-1.07), p < .001. Conclusions: An educational information session about immunization based on motivational interview techniques conducted during postpartum hospitalization could improve immunization during infancy.