A postpartum vaccination promotion intervention using motivational interviewing techniques improves short-term vaccine coverage: PromoVac study

Vaccination is widely considered to be one of the greatest advancements in public health. Vaccination programs have contributed substantially to the decline in mortality and morbidity of infectious diseases with major public health importance [1, 2]. To be successful in reducing the prevalence and incidence of vaccine-preventable diseases, vaccination programs rely on high and sustained vaccine uptake [3–5]. Vaccination is not mandatory and is free of charge in Quebec. According to the most recent childhood National Immunization Coverage Survey (conducted every 2 years), vaccination uptake by vaccine type at age 2 years in 2014 varied from 71 to 85% [6]. This low level of vaccine coverage (VC) in childhood vaccination 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 programs may be losing public confidence [7, 8].

Significant gaps in coverage in immunization programs have led to outbreaks of preventable diseases such as measles, whooping cough, rubella, and mumps, worldwide. For instance, in 2015, a large measles outbreak was traced to an unvaccinated traveler visiting Disneyland, which affected more than 20 US states, Mexico, and Canada, including 150 cases in an unvaccinated community in Quebec [9]. In addition, 13,726 cases of measles were reported between 1 November 2016 and 31 October 2017 in 30 European Union/European Economic Area member States, with the highest number of cases reported by Romania (5605) and Italy (4973). Among the cases with a known vaccination status, 87% were unvaccinated and 8% were vaccinated with a single dose, demonstrating that coverage failures may have contributed to outbreaks (https://ecdc.europa.eu/sites/portal/files/documents/Monthly-Measles-Rubella-monitoring-report-December-2017_0.pdf).

“Vaccine hesitancy” (VH) is a concept now frequently used in the discourse related to vaccine acceptance [10]. “VH” is described by the World Health Organization as the “delay in acceptance or refusal of vaccines, despite availability of vaccine services.” Vaccine-hesitant parents may accept with reluctance, delay or refuse one, some, or all vaccines [11].

Three effective interventions are known to increase vaccination uptake among populations: parent reminder and recall, multicomponent interventions that include education, and vaccination requirements for child care, school, and college attendance [12]. To date, there has been no evidence to suggest that education-only interventions were effective in improving VC [12]. Among the few studies that have addressed parental VH and refusal, no effective strategies have been proposed [13, 14]. With the increasing proportion of vaccine-hesitant parents, there is an important need to develop effective vaccination promotion strategies.

In this context, we developed an educational intervention program to be delivered at the maternity ward based on the motivational interviewing (MI) approach to promote early childhood immunization [15]. Described as a promising tool for the health promotion strategy [16], MI is a patient-centered communication style used to enhance the patient’s internal motivation for attitudinal change by exploring and solving inherent ambivalences [17]. Originally developed in the context of substance abuse, MI has also been applied for behavior change in several health-related fields such as nutrition, physical activity, and smoking cessation [18–20]. MI is based on four main principles: 1) empathizing with the client, 2) developing a discrepancy between their current and desired behavior, 3) dealing with resistance without antagonizing, preserving effective communication, and allowing clients to explore their views, and 4) supporting self-efficacy, i.e., the confidence in their ability to change [21]. The underlying spirit of MI is based on partnership, acceptance, compassion, and evocation. The goal is to engage the client in a collaborative working relationship, allowing the client to feel involved in the decision to change, in a respectful and non-judgmental atmosphere. Counseling based on MI involves five core communication skills: 1) asking open questions, 2) affirming, 3) reflective listening, 4) summarizing, and 5) informing and advising only if prior permission was given by the client.

An MI session delivered at a regional maternity ward in Quebec during the mother’s postpartum stay showed promising results with a significant 15% increase in the intention of mothers to vaccinate their infants at 2 months old [15]. The present study aimed to assess the impact of this novel educational strategy based on MI techniques, on the VC of infants at 3, 5, and 7 months of age.

The methods section adheres to the Transparent Reporting of Evaluations with Non-randomized designs (TREND) statement checklist guidelines [22].

This regional study was the first to assess the impact of a brief MI session during the postpartum stay on the short-term VC of infants. Our findings confirm our previous results, which revealed an increase of 15% in vaccine intention of mothers who received the intervention, and a significant increase in VC in infants [15].

However, due to study design limitations, conclusions should be made carefully. This study used a quasi-experimental design and was not a randomized control trial. The aim of this study was to assess the feasibility and the potential impact of the MI strategy in a regional cohort to conduct a future randomized controlled trial in case of positive results. The study limitations were attributed to the characteristics of the experimental and control groups, which were similar except for the proportion of cesarean births and the proportion of hospitalizations in the neonatology ward (these were higher in the control group because mothers or newborns requiring acute care were excluded from the study). The control group also showed a higher proportion of mothers with newborns that were not their first children. This difference between the two groups may have had an impact on the results of this study because we previously showed that the intention to vaccinate an infant at 2 months old was positively associated with having at least one child. Thus, the control group may have had a stronger intention to vaccinate than did the experimental group, which could have minimized the effects of the educational session. Moreover, as consenting mothers were not randomized to receive the intervention, there was no significant difference in the VC of children whose mothers did not receive the intervention (control group, primary refusals group, and secondary refusals or impossible intervention group), suggesting the absence of a selection bias. In addition, the immunization registry did not contain vaccination data for children who moved out of the region after their birth. Thus, the VC calculated in this study might be underestimated. However, this bias was non-differential, as relocations could have occurred both in the experimental and the control groups. Despite some improvements in the reminder and recall procedures by the Eastern Townships Public Health Department, the impact of the MI session may be considered to have resulted in the observed increase in the experimental group because reminders and recalls were likely addressed to both groups (experimental and control).

Despite the above limitations, the results showed that the MI session was effective, as a sustained increase (from 3.2 to 7.3%) in the VC of infants at 3, 5, and 7 months old was observed. Results of the ITT analysis were similar and also statistically significant, strongly reflecting the effectiveness of the study intervention. Moreover, the improvement in the VC observed at 7 months was significant even after adjusting for confounding variables. Indeed, the results showed that infants of mothers who received the MI session had an 8% higher chance of having a complete vaccination status at the age of 7 months than did children whose mothers did not receive the intervention. These improvements in the short-term infant VC are among the best reported in the literature [12, 13], and are highly encouraging, considering that delays in the first vaccination at 2 months old are associated with a higher probability of having an incomplete immunization status at 2 years of age [5, 27–32]. The significant increase in VC at 3, 5, and 7 months could thus predict an increase in VC for all childhood vaccines. Furthermore, this study confirmed our previous results showing an increase of 15% in the intention to vaccinate among mothers who received the MI session [15]. This indicates that the mother’s intention to vaccinate and immunization behavior are highly associated.

Traditional education methods have not been effective in addressing VH [33], 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 [34]. 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. Our study is the first to demonstrate the potential effectiveness of an immunization promotion strategy using the MI approach in the field of vaccination. Only two studies have used the MI techniques to promote immunization among adults [35, 36]. Although their results were promising, they were not significant, mostly because of the small sample size [36] and the specific targeted population (adults undergoing methadone maintenance treatment) [35]. A good communication strategy involves understanding people, establishing a respectful partnership and helping them to modify their behavior according to their capacities.

A major strength of this study was the availability of vaccination data from a regional immunization registry, allowing the study of the intervention’s impact on VC of a large birth cohort of nearly 3000 newborns. Moreover, as 95% of the deliveries in the Eastern Townships occurred at the maternity ward of the CHUS, our sample was representative of the total population of mothers of newborns in the region. Moreover, according to the Health Insurance Plan in Quebec, hospitalization of mothers during childbirth is free of charge and does not motivate mothers’ choice to give birth at home or in hospital. However, mothers who gave birth at home or in birth-houses were not included in the study. These mothers may have different opinions regarding vaccination and may have a higher tendency to not have their children immunized.

This regional study following a large birth cohort is the first to demonstrate the effectiveness of a brief educational intervention using the MI approach during the postpartum stay. In addition to an increase of 15% in the mothers’ intention to vaccinate their child, the intervention also significantly increased the VC of infants at 7 months old by 7%. 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 is critical. We suggest that MI may represent one of the most promising avenues of vaccination promotion strategies.