MomsTalkShots positively impacted pregnant women’s and mothers’ knowledge and perceptions of maternal and infant vaccines and the diseases they prevent. Among women initially intending not to vaccinate, MomsTalkShots increased perceived risk of maternal influenza disease and confidence in influenza vaccine efficacy. Among women with uncertain infant vaccine intentions, MomsTalkShots increased trust in obstetricians and pediatricians and substantially reduced safety concerns.
These findings correspond to our previous findings that MomsTalkShots substantially increased influenza vaccine uptake among pregnant women who initially did not intend to vaccinate during pregnancy [
48]. This contributes to the literature showing that changing attitudes can improve vaccine acceptance [
29,
35]. These findings are notable, as vaccine education is typically ineffective unless implemented in tandem with other proven interventions (such as provider prompts and standing orders), [
31,
66] with a few exceptions [
67‐
71]. MomsTalkShots’ impact may be partly due to its ability to tailor its content to individual vaccine intentions, KABs, and demographics, further supporting such an approach to vaccine education [
34,
35]. Also notable is the duration of impact; decreased safety concerns, increased perceived vaccine knowledge, and increased trust in obstetricians and pediatricians were found in women nearly a year after they received MomsTalkShots, despite evidence that didactic education often fades from memory after about a week [
72].
The only unexpected construct association found was that MomsTalkShots decreased perceived risk of infant pertussis. Education strategies based on correcting vaccine misinformation or exposure to fear appeals also have the potential to backfire among those with strong preexisting levels of vaccine hesitancy, [
73‐
75] and thus must be approached with caution and care. However, this decrease in perceived risk of infant pertussis was driven by a reduction in perceived susceptibility among women who received Tdap during pregnancy (Additional file
1: Appendix 5). Perceived severity increased after MomsTalkShots (Additional file
1: Appendix 1). So, women who received Tdap after learning how Tdap protects their infant from pertussis via MomsTalkShots correctly perceived a reduction in susceptibility of their infant to pertussis and correctly identified the increased severity of pertussis for infants.
Limitations
Our study design included randomization at both the practice/provider and the patient levels. We hypothesized that both interventions might impact KAB constructs, and there might be an improved impact when combined. However, only the patient level intervention (MomsTalkShots) appeared to have an impact; the number of construct associations found with the practice/provider intervention was less than expected by chance alone and the interaction between practice/provider and patient interventions was non-significant. So we focused our per protocol analysis on constructs in the main analysis to reduce redundancy and the chances of type 1 error. There were many insignificant associations that we did not explicitly comment on in this manuscript; they may indicate MomsTalkShots did not impact certain vaccine perceptions, especially among those not intending to vaccinate at baseline. Although we analysed each KAB construct both as a continuous score and a dichotomous indicator of an above-average score, we focused exclusively on the dichotomous analysis in the Results and corresponding tables, despite continuous measures typically providing greater power and precision than dichotomous measures derived from them. However, we found the dichotomous analyses to be much more interpretable and thus more useful for the main text. We have presented both analyses fully in the Appendices for transparency; aside from small differences in significance due to loss of power, the results of the dichotomous analysis (Additional file
1: Appendices 1–2) were highly consistent with the results of the continuous analysis (Additional file
1: Appendices 3–4), justifying our approach. MomsTalkShots’ decrease in perceived risk of infant pertussis being driven by women who received Tdap during pregnancy illustrates the potential effect modification of vaccination, which was not included in our analytic approach beyond further exploration of an unexpected result. Small numbers of women intending their children to receive no recommended vaccines did not provide enough power to justify stratifying by this group alone, so it was combined with those who intended their children to receive some (but not all) recommended vaccines. Although this made our stratification less precise, it increased our power and simplified our analysis. Even with this combination, power was still limited, leading to many potential associations that were close to but not quite statistically significant at the prespecified
p < 0.05 cutoff. This analysis focused on pregnant women and mothers and thus did not account for others who may be heavily involved in vaccine decisions for children, though data on partners, family and close friends of these pregnant women are published elsewhere [
55,
56]. Our sample was comprised mostly of highly educated white women, despite efforts to recruit from a geographically and socio-demographically diverse set of prenatal care practices. Finally, loss to follow-up with differential rates by baseline intention to vaccinate may have biased our data, especially from the final follow-up at 1 year after birth, as those who intended to vaccinate were more likely both to follow-up and to interact positively with MomsTalkShots.
Evaluation of MomsTalkShots through a RCT has high internal validity and provides compelling efficacy data. Our study included recruitment by study coordinators in obstetric practices using financial incentives, whereas in a real-world setting, strategies would be needed to encourage pregnant women and mothers to use MomsTalkShots without these incentives. While scale-up is not a challenge from a technical perspective, dissemination and support from healthcare providers, public health authorities, and other partners would be critical. Other similar interventions do not offer this potential combination of effectiveness and scalability. In-person training of providers to improve their vaccine communication with patients has been shown to be effective, but scale-up would be cost- and time-intensive [
52‐
54]. Several other educational vaccine apps and websites have been developed [
70,
71,
76‐
80]. These include:
ImmunizeCA, a smartphone app which helps Canadians manage their family’s immunizations by generating customized immunization schedules and reminder alerts for each family member [
77];
ReadyVax, a smartphone app providing access to evidence-based vaccine information for providers and patients [
79]; and
HPV Vaccine: Same Way, Same Day, a smartphone app which teaches evidence-based vaccine recommendation practices including motivational interviewing skills using simulated role-play scenarios [
80]. However, only one – a web-based social media intervention during pregnancy – demonstrated a significant positive effect on vaccine uptake, and its scalability is a challenge due to its reliance on public interactions with vaccine experts, whose time is limited and expensive [
70,
71]. MomsTalkShots is the only app or website that tailors information on vaccine attitudes, concerns and demographics. Further research is needed to identify characteristics beyond tailoring that make such apps and websites effective versus ineffective among various populations and settings.
The need for effective interventions to improve vaccine confidence and uptake has only increased since the conclusion of this study. The Coronavirus disease 2019 (COVID-19) pandemic has caused widespread morbidity and mortality, while disjointed government response has led to confusion, the unfortunate politicization of vaccination, and vaccine hesitancy coming to the forefront of public consciousness [
81,
82]. COVID-19 vaccines were at first particularly perplexing for pregnant women, given pregnant women’s exclusion from clinical trials but increased risk for severe illness from COVID-19 [
83]. As of June 2022, 71% of US pregnant women were fully vaccinated against COVID-19, compared to 77% of adults overall [
36]. However, most (95%) vaccinated pregnant women had been fully vaccinated before becoming pregnant. Promising early data on efficacy [
84‐
86] and safety [
87‐
89] of mRNA COVID-19 vaccines in pregnancy were eventually published, and the American College of Obstetricians and Gynecologists (ACOG) strongly supports vaccination against COVID-19 during pregnancy [
90].
Adaptation of MomsTalkShots for new vaccines and populations beyond English-speaking pregnant women in the US has the potential to improve vaccine knowledge and perceptions more broadly. We are currently updating and expanding MomsTalkShots to become “LetsTalkShots”, which will cover vaccines across the lifespan, including routine adolescent and adult vaccines such as HPV, influenza, and shingles. Crucially, MomsTalkShots has also been adapted to improve COVID-19 vaccine knowledge and perceptions by providing easily accessible, individually-tailored messages to assuage common concerns about COVID-19 vaccines (e.g., new technology, rushed timeline for development, long-term safety, fertility, safety in pregnancy) and appeal to populations with lower acceptance (e.g., pregnant women, ethnic minorities, younger age, less education, conservative political ideology) [
91‐
93]. This new iteration of MomsTalkShots, called “LetsTalkCovidVaccines”, is free and accessible for all at
http://letstalkcovidvaccines.com/. The content, design, and distribution of LetsTalkShots and LetsTalkCovidVaccines will be regularly assessed and upgraded, to reflect updates in science, incorporate new topics of concern, improve the user experience, and expand access, reach, and impact.