During the Coronavirus Disease 2019 (COVID-19) epidemic, many health professionals used social media to promote preventative health behaviors. We conducted a randomized controlled trial of the effect of a Facebook advertising campaign consisting of short videos recorded by doctors and nurses to encourage users to stay at home for the Thanksgiving and Christmas holidays (NCT04644328 and AEARCTR-0006821). We randomly assigned counties to high intensity (n = 410 (386) at Thanksgiving (Christmas)) or low intensity (n = 410 (381)). The intervention was delivered to a large fraction of Facebook subscribers in 75% and 25% of randomly assigned zip codes in high- and low-intensity counties, respectively. In total, 6,998 (6,716) zip codes were included, and 11,954,109 (23,302,290) users were reached at Thanksgiving (Christmas). The first two primary outcomes were holiday travel and fraction leaving home, both measured using mobile phone location data of Facebook users. Average distance traveled in high-intensity counties decreased by −0.993 percentage points (95% confidence interval (CI): –1.616, −0.371; P = 0.002) for the 3 days before each holiday compared to low-intensity counties. The fraction of people who left home on the holiday was not significantly affected (adjusted difference: 0.030; 95% CI: −0.361, 0.420; P = 0.881). The third primary outcome was COVID-19 infections recorded at the zip code level in the 2-week period starting 5 days after the holiday. Infections declined by 3.5% (adjusted 95% CI: −6.2%, −0.7%; P = 0.013) in intervention compared to control zip codes. Social media messages recorded by health professionals before the winter holidays in the United States led to a significant reduction in holiday travel and subsequent COVID-19 infections.

在 2019 年冠状病毒病 (COVID-19) 流行期间，许多卫生专业人员使用社交媒体来宣传预防性健康行为。我们对 Facebook 广告活动的效果进行了一项随机对照试验，该活动由医生和护士录制的短视频组成，以鼓励用户在感恩节和圣诞节假期呆在家里（NCT04644328 和 AEARCTR-0006821）。我们将县随机分配到高强度（n  = 410（386）在感恩节（圣诞节））或低强度（n = 410 (381))。在高强度县和低强度县，分别有 75% 和 25% 的随机分配的邮政编码向 Facebook 的大部分用户提供了干预。总共包括 6,998 (6,716) 个邮政编码，感恩节（圣诞节）覆盖了 11,954,109 (23,302,290) 个用户。前两个主要结果是假期旅行和离家比例，两者均使用 Facebook 用户的手机位置数据进行衡量。与低强度县相比，每个假期前 3 天，高强度县的平均旅行距离减少了 -0.993 个百分点（95% 置信区间 (CI)：–1.616，-0.371；P = 0.002）。假期离家的比例没有受到显着影响（调整后差异：0.030；95% CI：-0.361, 0.420；P = 0.881）。第三个主要结果是在假期后 5 天开始的 2 周内在邮政编码级别记录的 COVID-19 感染。与对照邮政编码相比，干预措施的感染率下降了 3.5%（调整后的 95% CI：-6.2%，-0.7%；P = 0.013）。卫生专业人员在美国寒假前记录的社交媒体消息导致假期旅行和随后的 COVID-19 感染显着减少。