PurposeTechnology has eased access to information. During the ongoing COVID-19 pandemic, ease of access and transmission of information via social media has led to ambiguity, misinformation and uncertainty. This research studies the aforementioned behaviours of information sharing and verification related to COVID-19, in the context of social media.Design/methodology/approachTwo studies have been carried out. Study 1, with Indian social media users, is a two-factor between-subjects experimental design that investigated the effect of message polarity (positive versus negative) and message type (news versus rumour) on the dissemination and verification behaviour of COVID-19-related messages. The study also investigated the mediation of perceived message importance and health anxiety. Study 2 is a replica study conducted with US users.FindingsThe study finding revealed significantly higher message sharing for news than rumour. Further, for the Indian users, message with positive polarity led to higher message sharing and message with negative polarity led to higher verification behaviour. On the contrary, for the US users, message with negative polarity led to higher message sharing and message with positive polarity led to higher verification behaviour. Finally, the study revealed message importance mediates the relationship of message type and message sharing behaviour for Indian and US users; however, health anxiety mediation was significant only for Indian users.Practical implicationsThe findings offer important implications related to information regulation during a health crisis. Unverified information sharing is harmful during a pandemic. The study sheds light on this behaviour such that stakeholders get insights and better manage the information being disseminated.Originality/valueThe study investigates the behaviour of sharing and verification of social media messages between users containing health information (news and rumour) related to the ongoing COVID-19 pandemic.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-07-2020-0282