Interventions involving nudge theory for COVID-19 vaccination: A systematic review and meta-analysis.

Objective: New approaches to mitigate vaccine hesitancy and improve vaccine uptake are urgently needed. Nudging has shown effective results in several health areas. However, the effectiveness of interventions involving nudge theory in increasing COVID-19 vaccination remains unclear.

Method: We searched PubMed, Web of Science, and Scopus for randomized controlled trials published before December 31, 2022, to determine whether interventions involving nudge theory improved COVID-19 vaccination behavior and intent. Risk ratio (RR) and a 95% confidence interval (CI) were used as pooled measures to assess vaccination behavior. Intention to vaccinate was reported in a narrative synthesis.

Results: Sixteen randomized controlled trials involving 176,125 participants were included. Interventions involving nudge theory weakly boosted the COVID-19 vaccine uptake rate (RR = 1.21, 95% CI [1.07, 1.36], p < .01). Subgroup analysis showed a weak positive effect of social norms (RR = 2.04, 95% CI [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]). Nudge interventions integrating multiple components were more efficacious in increasing vaccination rates compared to nudge alone. The effect of nudging interventions weakened over time (p < .001). Most studies (10 of 11) involving vaccination intention outcomes showed positive or partially positive results.

Conclusions: Interventions involving nudge theory can promote COVID-19 vaccination behavior and intentions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).