The COVID-19 pandemic has brought on an unprecedented amount of information about the virus and vaccination, varying significantly across information channels. While extant research shows that excessive information leads to overload and less elaboration, few studies have examined factors associated with information overload and elaboration. Considering the trend that we likely receive information on the same topics from different communication channels daily, this study sought to understand how cross-channel differences in the information were associated with information overload and subsequent elaboration. The survey assessed 471 participants' consumption of COVID-19 information across different channels (interpersonal communication vs. social media), concern about information quality, information overload, information elaboration, health literacy, and demographic characteristics in February 2021. Our findings confirmed that greater information overload was negatively associated with more information elaboration. Using a moderated mediation model, we found that people who received more information from social media, compared to those who received equal amounts of information from both social media and interpersonal communications, reported more information overload and less elaboration. Additionally, we found that people who experienced greater information overload and held greater concern about information quality tended to elaborate more information. All analyses were controlled for health literacy. Theoretical and practical implications were discussed.