Different vaccination debunking interventions: a randomized, controlled experiment estimating "backfiring" and...

Misinformation about vaccines can hinder efforts to increase immunization rates. Attempts to correct misinformation often use one of three common message structures. The effectiveness of these message structures is unclear, and concerns have been raised that some can "backfire" by weakening vaccination intentions.

We conducted a pre-registered, survey-embedded experiment to test the effect of three different misinformation-correction message structures on vaccine intentions to receive an initial Covid-19 vaccine or booster. The sample was limited to U.S. adults with vaccination safety concerns. Participants were randomized to either a no-message control arm or one of three message structure conditions: (1) a myth followed by fact; (2) a fact, followed by a myth, and then fact again; (3) or fact only. Participants reported their intentions to receive the Covid-19 initial vaccination or booster and, using ordinal logistic regression models, we examined the effect of condition on intentions.

The experiment included a group (n = 892) of racially and ethnically diverse adults. Among those who had received initial Covid-19 vaccination, exposure to the myth-followed-by-fact message structure was associated with strengthened booster intentions compared to the control (B = 0.81, p < .01). Among those who had not begun the initial Covid-19 vaccination series, the strength of intention to start vaccination did not differ between the control condition in any of the three misinformation-correction conditions.

Despite fears that debunking can "backfire," none of the results support that concern because intentions were not weakened. The myth-followed-by-fact message structure significantly strengthen intentions, but only among the group that had received the initial vaccination. The two other debunking approaches had no effect on vaccination intentions.