Doctors’ and Nurses’ Social Media Ads Reduced Holiday Travel and COVID-19 infections: A cluster randomized controlled trial in 13 States

Abstract

During the COVID-19 epidemic, many health professionals started using mass communication on social media to relay critical information and persuade individuals to adopt preventative health behaviors. Our group of clinicians and nurses developed and recorded short video messages to encourage viewers to stay home for the Thanksgiving and Christmas Holidays. We then conducted a two-stage clustered randomized controlled trial in 820 counties (covering 13 States) in the United States of a large-scale Facebook ad campaign disseminating these messages. In the first level of randomization, we randomly divided the counties into two groups: high intensity and low intensity. In the second level, we randomly assigned zip codes to either treatment or control such that 75% of zip codes in high intensity counties received the treatment, while 25% of zip codes in low intensity counties received the treatment. In each treated zip code, we sent the ad to as many Facebook subscribers as possible (11,954,109 users received at least one ad at Thanksgiving and 23,302,290 users received at least one ad at Christmas). The first primary outcome was aggregate holiday travel, measured using mobile phone location data, available at the county level: we find that average distance travelled in high-intensity counties decreased by −0.993 percentage points (95% CI −1.616, −0.371, p-value 0.002) the three days before each holiday. The second primary outcome was COVID-19 infection at the zip-code level: COVID-19 infections recorded in the two-week period starting five days post-holiday declined by 3.5 percent (adjusted 95% CI [-6.2 percent, −0.7 percent], p-value 0.013) in intervention zip codes compared to control zip codes.One sentence summaryIn a large scale clustered randomized controlled trial, short messages recorded by health professionals before the winter holidays in the United States and sent as ads to social media users led to a significant reduction in holiday travel, and to a decrease in subsequent COVID-19 infection at the population level.

Randomized trials on non-pharmaceutical interventions for COVID-19: a scoping review

“…The trials planned to recruit a median of 1700 participants (IQR 588–9500, range 30–35 256 399) with a median planned duration of 8 months (IQR 3–14, range 1–24). The largest trial assessed the impact of Facebook advertisements to prevent travelling and family reunions during Thanksgiving and Christmas with >35 million participants, 28 the shortest trial assessed the audience infection rate 8 days after an indoor music event. 29 A typical randomised trial on NPIs randomly allocated individuals (n=23, 56.1%), rather than clusters (n=18, 43.9%), to two comparison groups (n=38, 92.7%) and assessed a COVID-19-related primary outcome (n=33, 80.5%) that was laboratory confirmed (n=30, 73.2%).…”

Randomized trials on non-pharmaceutical interventions for COVID-19 as of August 2021: a meta-epidemiological analysis

“…We The trials planned to recruit a median of 1,700 participants (IQR, 588 to 9,500, range 30 to 35,256,399) with a median planned duration of 8 months (IQR, 3 to 14, range 1 to 24). The largest trial assessed the impact of Facebook advertisements to prevent traveling and family reunions during Thanksgiving and Christmas with >35 million participants 12 , the shortest trial assessed the audience infection rate 8 days after an indoor music event. 13 A typical randomized trial on NPIs randomly allocated individuals (n=23, 56.1%), rather than clusters (n=18, 43.9%), to two comparison groups (n=38, 92.7%) and assessed a COVID-19-related primary outcome (n=33, 80.5%) that was laboratoryconfirmed (n=33, 80.5%).…”