Digital Health Communication and Vaccine Confidence: Secondary Analysis of Aggregated Randomized Brand Lift Studies in Mexico.

Publication date: Dec 08, 2025

Digital vaccination campaigns are increasingly used to address declining vaccine confidence, yet evidence from large-scale, real-world interventions in middle-income countries is limited. Meta’s Brand Lift Studies (BLS), which use randomized test-control exposure, provide Bayesian esti-mates of attitudinal shifts resulting from digital content. Mexico, with over 88. 6 million active internet users, provides a setting to evaluate the impact of targeted campaigns on vaccine atti-tudes. This study evaluated the impact of five digital vaccination campaigns implemented by the Aso-ciacicF3n Mexicana de VacunologcEDa (@Vacunologia) on Facebook and Instagram in Mexico be-tween 2021 and 2022 on key attitudinal constructs related to COVID-19 vaccine confidence. This study used a retrospective ecological design, we analyzed aggregated BLS results for five campaigns targeting different audiences and vaccination themes. Measured outcomes included standard ad recall, perceived importance, perceived safety, perceived efficacy, and concerns about side effects. Statistical significance within the BLS framework was defined as an incre-mental lift of ≥2 percentage points with ≥90% posterior probability of replication-a threshold consistent with Meta’s operational Bayesian approach. Exploratory comparisons across cam-paigns were conducted using one-way analysis of variance (ANOVA), unpaired t-tests, and Fish-er’s Exact Tests. Campaigns reached 84. 9 million accounts and generated 179. 4 million impressions with a total investment of USD 215,600. All campaigns produced statistically significant improvements in at least one attitudinal outcome (Bayesian threshold ≥90%). Standard ad recall increased in four campaigns (ANOVA, P

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