Plain Language vs Standard Format for Youth Understanding of COVID-19 Recommendations: A Randomized Clinical Trial.

To ensure that youths can make informed decisions about their health, it is important that health recommendations be presented for understanding by youths. To compare understanding, accessibility, usability, satisfaction, intention to implement, and preference of youths provided with a digital plain language recommendation (PLR) format vs the original standard language version (SLV) of a health recommendation. This pragmatic, allocation-concealed, blinded, superiority randomized clinical trial included individuals from any country who were 15 to 24 years of age, had internet access, and could read and understand English. The trial was conducted from May 27 to July 6, 2022, and included a qualitative component. An online platform was used to randomize youths in a 1:1 ratio to an optimized digital PLR or SLV format of 1 of 2 health recommendations related to the COVID-19 vaccine; youth-friendly PLRs were developed in collaboration with youth partners and advisors. The primary outcome was understanding, measured as the proportion of correct responses to 7 comprehension questions. Secondary outcomes were accessibility, usability, satisfaction, preference, and intended behavior. After completion of the survey, participants indicated their interest in completing a 1-on-1 semistructured interview to reflect on their preferred digital format (PLR or SLV) and their outcome assessment survey response. Of the 268 participants included in the final analysis, 137 were in the PLR group (48.4% female) and 131 were in the SLV group (53.4% female). Most participants (233 [86.9%]) were from North and South America. No significant difference was found in understanding scores between the PLR and SLV groups (mean difference, 5.2%; 95% CI, -1.2% to 11.6%; P = .11). Participants found the PLR to be more accessible and usable (mean difference, 0.34; 95% CI, 0.05-0.63) and satisfying (mean difference, 0.39; 95% CI, 0.06-0.73) and had a stronger preference toward the PLR (mean difference, 4.8; 95% CI, 4.5-5.1 [4.0 indicated a neutral response]) compared with the SLV. No significant difference was found in intended behavior (mean difference, 0.22 (95% CI, -0.20 to 0.74). Interviewees (n = 14) agreed that the PLR was easier to understand and generated constructive feedback to further improve the digital PLR. In this randomized clinical trial, compared with the SLV, the PLR did not produce statistically significant findings in terms of understanding scores. Youths ranked it higher in terms of accessibility, usability, and satisfaction, suggesting that the PLR may be preferred for communicating health recommendations to youths. The interviews provided suggestions for further improving PLR formats. ClinicalTrials.gov Identifier: NCT05358990.