A Postpartum Vaccination Promotion Intervention Using Motivational Interviewing Techniques Improves Short-Term Vaccine Coverage: PromoVac Study

"With the increasing proportion of vaccine-hesitant parents, there is an important need to develop effective vaccination promotion strategies."

Vaccination is not mandatory and is free of charge in Quebec, Canada. The National Immunization Coverage Survey found that vaccination uptake by vaccine type at age 2 years in 2014 varied from 71 to 85%. This low level of vaccine coverage (VC) could be explained by the increasing number of parents who are ambivalent regarding the necessity and safety of vaccines, and it is possible that vaccination programmes may be losing public confidence. In that context, this study aimed to assess the impact of an educational strategy of vaccination promotion based on motivational interviewing (MI) techniques designed for parents and delivered at the maternity ward of the Centre hospitalier universtaire de Sherbrooke (CHUS), located in Quebec's Eastern Townships region, for the VC of infants at 3, 5, and 7 months of age.

MI is a patient-centred communication strategy for helping individuals to make a decision and elicit and strengthen their motivation to change behaviour based on the person's own arguments for change. Based on the MI approach, this intervention is carried out in simple and understandable language in order to foster discussion and allow questions from parents rather than provide prescriptive, unequivocal, and unidirectional information. The MI intervention was developed according to 4 Prochaska's stages of change (pre-intention or pre-contemplative; intention or complemplative; preparation or determination; and action) and lasts approximately 15 to 20 minutes. MI involves:

1. Expressing empathy: MI emphasises understanding and acceptance of the client's knowledge, attitudes, and experiences rather than the physician's role as expert.
2. Developing discrepancy between the client's current and desired behaviour.
3. Rolling with resistance and not against it to prevent communication rupture and allowing them to explore their views.
4. Supporting self-efficacy, i.e. the confidence in their ability to change.

The intervention content was adapted from 2 existing theoretical frameworks: 1) the Health Belief Model (HBM) and 2) the transtheoretical model of behaviour change. Based on this composite model, the intervention was adapted to each participating family according to the current intention of the parent to vaccinate his/her newborn at 2 months of age.

An individual educational information session regarding immunisation of infants aged 2, 4, and 6 months was (experimental group) or was not (control group) administered using MI techniques to consenting mothers 24 to 48 hours after the delivery in their rooms. Absolute VC increases at 3, 5, and 7 months in the experimental group were calculated, and the relative risks (RR) with the respective 95% confidence intervals (CIs) were computed using univariate logistic regression with the generalised estimating equations (GEE) procedure. Multivariate regression using GEE was used to adjust for confounding variables.

The study used vaccination data from a regional immunisation registry, allowing the study of the intervention's impact on VC of a large birth cohort of nearly 3,000 newborns. In the experimental and control groups, 1,140 and 1,249 newborns were included, respectively. A significant increase in VC of 3.2, 4.9, and 7.3% was observed at 3, 5, and 7 months of age (P < 0.05), respectively. The adjusted RR of the intervention's impact on vaccination status at 7 months of age was 1.08 (95% CI: 1.03-1.14) (P = 0.002). These findings confirm the results of a previous study by these same researchers, which revealed an increase of 15% in vaccine intention of mothers who received the intervention and a significant increase in VC in infants. This indicates that the mother's intention to vaccinate and immunisation behaviour are highly associated. However, due to study design limitations, e.g., it used a quasi-experimental design and was not a randomised control trial, the researchers stress that conclusions should be made carefully.

In reflecting on the findings, the researchers write: "Traditional education methods have not been effective in addressing VH..., while some studies have shown that attempting to convince vaccine-hesitant parents to vaccinate their child by giving them more facts may be counterproductive and increase hesitancy....On the contrary, the high level of acceptability and effectiveness of the PromoVac strategy could be related to the use of the MI techniques. Indeed, the use of the MI approach facilitates a respectful and empathetic discussion of concerns about vaccinations, and helps to build a strong relationship between the parents and the nurses. Parents are given an opportunity to talk freely about their concerns and ask questions about vaccinations without feeling judged. The intervention is adapted to the parents' needs, based on their own concerns and questions, and therefore avoids giving them unnecessary or unwanted information. The nurses were able to help parents to explore their own ambivalence and to help them find their own arguments for change in order to make an informed decision about their child's vaccination....A good communication strategy involves understanding people, establishing a respectful partnership and helping them to modify their behavior according to their capacities."

In conclusion: "A forthcoming study will assess the intervention's impact on long-term VC. This study presents a proof of concept of the MI intervention, and a randomized controlled trial may thus be conducted to validate these results. The need for effective strategies to tackle VH [vaccine hesitancy] is critical. We suggest that MI may represent one of the most promising avenues of vaccination promotion strategies."