Vaccination Hesitancy in the Antenatal Period: A Cross-Sectional Survey

"[T]his study provides further strong justification to talk with women about vaccination during pregnancy and particularly to ensure that first-time mothers are offered assistance in making these important decisions."

This study looks at the antenatal period, a time when many parents explore and consolidate vaccination attitudes, in New South Wales (NSW) north coast, Australia. This particular area has been ranked the lowest amongst Australia's 31 Primary Health Network areas, with 89.8%, 87.2%, and 90.3% of children fully vaccinated at 1, 2, and 5 years of age respectively in 2015/16. In general, vaccine safety scares, whether factual or fabricated, can erode confidence and motivate rapid and sustained reductions in coverage. In an era when, rather than relying on the advice of experts or authorities, individuals often assess risks and modify their behaviours as new information becomes available, episodic undermining of confidence in vaccines could threaten coverage levels. Furthermore, research has shown that the antenatal period is a time when many parents explore and consolidate their vaccination attitudes and therefore could be a pivotal period for study to improve understanding of vaccination decisions - particularly in a region with the lowest coverage rates nationally. Better understanding of parents' vaccination attitudes and actions within this region may guide strategies to improve uptake.

This article reports the attitudes, intentions, and vaccination behaviours of pregnant women attending antenatal clinics at public hospitals within the NSW north coast between September 2015 and July 2016. A total of 231 women attending public antenatal clinics at 6 hospitals completed a 10-minute cross-sectional survey capturing stage of decision-making and decisional conflict as well as vaccination hesitancy, attitudes, intentions, and actions. For consented children, immunisation status was assessed at 8 months using the Australian Immunisation Register. (Vaccination completeness was assessed for diphtheria, tetanus, pertussis, polio, haemophilus influenza b, hepatitis B, pneumococcal disease, and rotavirus.)

The study confirms that most expectant mothers make decisions about vaccination before or during their pregnancy: 81% of participating women reported they had made a firm decision about vaccination of their expected child, and a further 8% indicated that while they had made a decision, they might reconsider it before acting. Fewer first-time mothers (77.5%) than experienced mothers (94.5%) reported making a decision before or during pregnancy. About one-third (35.5%) of first-time mothers were undecided during their second trimester, and by third trimester, 14.9% of first-time mothers had still not decided about vaccinating their newborn.

Most respondents (92.2%) wanted their new baby to receive all recommended vaccinations, though many had high or moderate levels of concern about vaccine side effects (25.4%), safety (23.6%), and effectiveness (23.1%). Overall, 65.3% of respondents assessed themselves as "not at all hesitant" about childhood vaccination, 25.3% as "not too hesitant", 3.6% were somewhat hesitant, 2.2% were very hesitant, and 3.6% were not sure. Compared to the "not at all" hesitant, other pregnant women were 14 times more likely to be concerned about vaccine safety, 16 times more likely to be concerned about side effects, and 6 times more likely to have concerns about vaccine effectiveness.

Those who indicated any level of hesitancy were more likely to report ever delaying a vaccine (OR=9.2, 1.8-46.6) and more likely to report ever deciding against vaccinating a child (OR=9.5, 1.0-87.3) for reasons other than illness or allergy. Increased hesitancy was associated with decreased confidence in the schedule (p<0.001), decreased trust in child's doctor (p<0.0001), decreased perceived protection from disease (p<0.05), and increased decisional conflict on all measured subscales (p<0.0001). More hesitant respondents reported lower likelihood of contracting a vaccine-preventable disease in Australia if unvaccinated.

First-time mothers had higher decisional conflict on values clarity, support, and uncertainty sub-scales, placing them at higher risk of decisional delay or feeling unsure about implementing their decisions. First-time mothers were 3 times more likely than others (odds ratio (OR)=3.40, 95% confidence interval (CI) 1.34-8.60) to identify as unsure, somewhat, or very hesitant. They were 5 times more likely to be unsure that the benefits of vaccines outweigh their risks.

Respondents who strongly supported childhood vaccination showed higher levels of trust in their child's doctor (mean=9.30, 9.11-9.48) than those who generally supported childhood vaccination (7.56, 6.82-8.29) and those who opposed or were ambivalent (4.22, 1.57-6.88) (p<0.0001). Similarly, those who were "not at all hesitant" reported higher levels of trust (9.43, 9.25-9.61) than the "not too hesitant" (8.51, 8.07-8.95) and the very/somewhat hesitant or unsure (5.76, 4.23-7.30) (p<0.0001).

Social influences were important in respondents' vaccination decisions. Mothers who expressed any level of hesitancy (compared to "not at all hesitant") were less likely to strongly agree that people important to them supported them to vaccinate their child (OR=0.21, 0.11-0.41) and less likely to strongly agree that people important to them would vaccinate their own child (OR=0.21, 0.12-0.37).

One hundred women (43.7% of respondents) consented to access of their babies' vaccination records. By 8 months of age, 83.2% of infants were fully vaccinated. Those with none or a few minor concerns were over 8 times more likely than others to vaccinate on schedule (OR=8.7, 1.3-56.7).

The researchers reflect: "These findings portray the complexity and impact of psychosocial and other factors on pregnant women's immunisation attitudes, intentions and behaviours....The findings also highlight the frailty underlying high uptake of vaccines and high levels of support for vaccination despite underlying safety concerns.... This confidence gap poses a risk to high coverage should a vaccine safety scare emerge and reflects the interplay between public confidence in vaccination and vaccine hesitancy, particularly in response to vaccine safety scares."

They indicate that the findings also suggest there may be benefit from engaging with women about vaccination decisions during family planning and early in pregnancy, particularly for women expecting their first child. Midwives may be "uniquely well-placed to support expectant and new mothers to make informed decisions about maternal and infant vaccination. However, some midwives find aspects of a vaccination advocacy role challenging due to the need to reconcile professional preferences for women's autonomy in decision-making or, for a significant minority, holding concerns about the safety, necessity and timing of vaccinations but working within the context of strident public health advocacy for timely vaccination of infants....Despite these challenges, significant positive associations between provision of immunisation education and support during the antenatal period and uptake of childhood immunisation have been demonstrated in a range of settings including within a cluster randomised trial in Japan and cross-sectional studies in Nigeria and Cameroon."

There has been research, and some debate, on exactly what type of communication interventions may be appropriate in terms of when and how to provide information about vaccination. For example, in a cluster-randomised controlled trial, Saito and colleagues found that mothers who received a series of short, interactive information sessions during pregnancy, soon after delivery, and when the baby was 1 month old reported improved positive injunctive social and descriptive norms (moral perceptions of what most people do and what an individual should do, respectively) and increased their perceptions of vaccine benefits and were more likely than controls to vaccinate their child with mandated, but not voluntary, vaccines. "However, the approach taken and content of information sessions needs to be chosen carefully. 'Knowledge deficit' approaches to address vaccine hesitancy have not been successful,...and poorly executed attempts to correct misinformation can backfire."

The researchers conclude by suggesting that "further research should focus on optimising the timing, content and delivery style of perinatal interventions that are acceptable to those providing care and that address the specific concerns of parents who are unsure about vaccinating their newborn child."