Web-Based Tailored Messaging to Increase Vaccination: A Randomized Clinical Trial

BACKGROUND: To increase vaccine acceptance, we created a Web-based the “Vaccines and Your Baby” intervention (VAYB) that provided new parents with vaccine information messages tailored to vaccine beliefs and values. We evaluated the effectiveness of the VAYB by comparing timely uptake of infant vaccines to an untailored version of the intervention (UT) or usual care intervention (UC) only. METHODS: Between April 2016 and June 2019, we conducted a randomized clinical trial. Pregnant women and new parents were randomly assigned to the VAYB, UT, or UC arms. In the VAYB and UT arms, participants were exposed to interventions at 4 time points from pregnancy until their child was 15 months of age. The primary outcome was up-to-date status for recommended vaccines from birth to 200 days of age. A modified intent-to-treat analysis was conducted. Data were analyzed with logistic regression to generate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We enrolled 824 participants (276 VAYB, 274 UT, 274 UC), 143 (17.4%) of whom were lost to follow-up. The up-to-date rates in the VAYB, UT, and UC arms were 91.44%, 92.86%, and 92.31%, respectively. Infants in the VAYB arm were not more likely to be up to date than infants in the UC arm (OR = 0.89; 95% CI, 0.45–1.76) or in the UT arm (OR = 0.82; 95% CI, 0.42–1.63). The odds of being up to date did not differ between UT and UC arms (OR = 1.08; 95% CI, 0.54–2.18). CONCLUSIONS: Delivering Web-based vaccine messages tailored to parents’ vaccine attitudes and values did not positively impact the timely uptake of infant vaccines.