Coverage of Transmission of COVID-19 Information on Successive Samples of YouTube Videos.

Mitigating transmission of SARS-Co-2 virus is critical to stopping the COVID-19 pandemic. Messages about the pandemic on YouTube reach millions of people and should be a part of a more comprehensive strategy for educating the public to reduce transmission. We examined successive samples of the 100 most widely viewed YouTube videos regarding COVID-19 at three time points between January and June 2020 and examined characteristics of videos that specifically mentioned COVID-19 transmission. We described the cumulative and mean number of views, video length, and video source and assessed differences across the samples. Historical events and confirmed worldwide cases are compared with cumulative views of videos mentioning disease transmission over time. Across the three successive samples, views for all videos increased from ~ 125 million to over 560 million views, and from ~ 63 million to more than 273 million for those videos specifically mentioning disease transmission, respectively. This increase coincided with the increase in the worldwide number of cases and the occurrence of COVID-19 transmission informational milestones. Despite its importance for community mitigation, the majority of the widely viewed videos we sampled did not specifically mention disease transmission. Because of its very widespread reach, YouTube can be an effective way to communicate with the public, especially to those who have lower levels of reading literacy and who may be inclined to search for information on YouTube. Greater efforts are needed to more fully realize the potential of YouTube for educating the public about COVID-19 transmission.