Introduction: To manage the rapid rise of misleading information on the coronavirus disease (COVID-19) during the pandemic, the Breakthrough ACTION project developed a theory-based rumor-tracking system to inform Guyana's COVID-19 communication campaign.
Methods: The rumor-tracking project used the extended parallel processing model (EPPM) to identify and categorize rumors reflecting perceived high versus low vulnerability to COVID-19 and high versus low efficacy of engaging in recommended COVID-19 prevention behaviors. The project designed contextually relevant social and behavior change messages, called "MythBusters," responded to rumor categories with the following objectives: (1) high perceived vulnerability and high efficacy rumors included a call to action; high perceived vulnerability and low efficacy rumors educated about effective and achievable solutions; (3) low perceived vulnerability and high efficacy rumors educated about risk; and (4) low perceived vulnerability and low efficacy rumors educated about risk and effective and achievable solutions.