Nudging vaccination against COVID-19: A systematic review and meta-analysis

Abstract

Abstract Background: New approaches to mitigate vaccine hesitancy (VH) and improve vaccine uptake and willingness are urgently needed. Nudging is a new approach that has shown effective results in several areas of health. However, the effectiveness is unclear regarding nudging interventions to improve intentions and behaviors related to COVID-19 vaccination. Methods: We searched PubMed, Web of Science, and Scopus until August 5, 2022. Randomized controlled trials (RCTs) were considered to determine whether nudging improved COVID-19 vaccination behavior and intent. The risk ratio (RR) and 95% confidence interval (CI) were used as pooled measures to assess vaccination behavior. Intention to vaccinate was reported in the narrative synthesis. Results: A total of 15 RCTs involving 167,127 individuals were included. Nudge strategies significantly boosted the COVID-19 vaccine uptake rate (RR: 1.19, 95% CI [1.07, 1.33], p < 0.01). Subgroup analysis showed that there was a weak positive effect on vaccine uptake of social norms (RR: 2.04, 95% Cl [1.61, 2.57]), defaults (RR: 1.32, 95% CI [1.03, 1.69]), and salient reminders (RR: 1.19, 95% CI [1.04, 1.36]). Additionally, the effect of nudging interventions on COVID-19 vaccine uptake weakened over time(p < 0.0001). Most studies (9 of 10) involving vaccination intention outcomes showed positive or partially positive results. Conclusion: Nudging interventions can promote COVID-19 vaccination behavior and intentions, albeit with small magnitude, and need to be combined with other intervention strategies to promote vaccination.