This study examines the diffusion of information about COVID-19 across major social media platforms, including Twitter, Instagram, YouTube, Reddit, and Gab. The authors analyze user engagement and interest in the COVID-19 topic, using epidemic models to characterize the basic reproduction number ($R_0$) for each platform. They find that all platforms exhibit similar user engagement patterns, with mainstream platforms like YouTube and Twitter showing higher volumes of interactions. The study also identifies the spread of misinformation from questionable sources and compares the impact of reliable and unreliable sources on information diffusion. The results suggest that the interaction patterns and audience dynamics of each platform play a crucial role in the spread of information and misinformation. The authors conclude by measuring rumor amplification parameters for each platform, highlighting the need for more efficient epidemic models and tailored communication strategies to address the infodemic during public health crises.This study examines the diffusion of information about COVID-19 across major social media platforms, including Twitter, Instagram, YouTube, Reddit, and Gab. The authors analyze user engagement and interest in the COVID-19 topic, using epidemic models to characterize the basic reproduction number ($R_0$) for each platform. They find that all platforms exhibit similar user engagement patterns, with mainstream platforms like YouTube and Twitter showing higher volumes of interactions. The study also identifies the spread of misinformation from questionable sources and compares the impact of reliable and unreliable sources on information diffusion. The results suggest that the interaction patterns and audience dynamics of each platform play a crucial role in the spread of information and misinformation. The authors conclude by measuring rumor amplification parameters for each platform, highlighting the need for more efficient epidemic models and tailored communication strategies to address the infodemic during public health crises.