Evidence on repeating vaccination misinformation or "myths" in debunking text is inconclusive; repeating myths may unintentionally increase agreement with myths or help discredit myths. In this study we aimed to compare the effect of repeating vaccination myths and other text-based debunking strategies on parents’ agreement with myths and their intention to vaccinate their children.

For this online experiment we recruited 788 parents of children aged 0 to 5 years; 454 (58%) completed the study. We compared 3 text-based debunking strategies (repeating myths, posing questions, or making factual statements) and a control. We measured changes in agreement with myths and intention to vaccinate immediately after the intervention and at least 1 week later. The primary analysis compared the change in agreement with vaccination myths from baseline, between groups, at each time point after the intervention.

There was no evidence that repeating myths increased agreement with myths compared with the other debunking strategies or the control. Posing questions significantly decreased agreement with myths immediately after the intervention compared with the control (difference: –0.30 points, 99.17% confidence interval: –0.58 to –0.02, P = .004, d = 0.39). There was no evidence of a difference between other debunking strategies or the control at either time point, or on intention to vaccinate.

Debunking strategies that repeat vaccination myths do not appear to be inferior to strategies that do not repeat myths.

在揭穿文本中重复疫苗接种错误信息或“神话”的证据尚无定论；重复神话可能会无意中增加对神话的认同或帮助诋毁神话。在这项研究中，我们旨在比较重复疫苗接种神话和其他基于文本的揭穿策略对父母对神话的认同以及他们为孩子接种疫苗的意图的影响。

对于这个在线实验，我们招募了 788 名 0 至 5 岁儿童的家长；454 (58%) 人完成了研究。我们比较了 3 种基于文本的揭穿策略（重复神话、提出问题或做出事实陈述）和一个对照。我们测量了干预后立即和至少 1 周后与神话和接种意图的一致性变化。主要分析比较了干预后每个时间点与基线、组间和疫苗接种神话的一致性变化。

与其他揭穿策略或对照相比，没有证据表明重复神话增加了与神话的一致性。与对照组相比，在干预后立即提出问题显着降低了与神话的一致性（差异：–0.30 分，99.17% 置信区间：–0.58 至 –0.02，P = .004，d = 0.39）。没有证据表明其他揭穿策略或控制在任一时间点或疫苗接种意图方面存在差异。

揭穿重复疫苗接种神话的策略似乎并不逊于不重复神话的策略。