Government social media is widely used for providing updates to and engaging with the public in the COVID-19 pandemic. While Facebook is one of the popular social media used by governments, there is only a scant of research on this platform. This paper aims to understand how government social media should be used and how its engagement changes in prodromal, acute and chronic stages of the pandemic. We collected 1664 posts and 10,805 comments from the Facebook pages of the Macao government from 1 January to 31 October 2020. Using word frequency and content analysis, the results suggest that the engagement was relatively low at the beginning and then surged in the acute stage, with a decreasing trend in the chronic stage. Information about public health measures maintained their engagement in all stages, whereas the engagement of other information was dropping over time. Government social media can be used for increasing vigilance and awareness in the prodromal stage; disseminating information and increasing transparency in the acute stage; and focusing on mental health support and recovery policies in the chronic stage. Additionally, it can be a tool for controlling rumors, providing regular updates and fostering community cohesion in public health crises.

BACKGROUND Government social media is widely used for providing updates to and engaging with the public in the COVID-19 pandemic, and Facebook is one of the popular social media platforms used by governments. However, there is only a scant of research focusing on these two areas. As the global pandemic has been easing in some places, users also react differently on social media to the messages from governments, which prompts more research in the post-pandemic time. OBJECTIVE This study aims to understand how government social media is used and how its engagement changes in different stages throughout the pandemic. Macao is one of the jurisdictions in the world that has suppressed the transmissions of COVID-19. The case study of Macao can also provide insights for the recovery period after the pandemic. METHODS Posts from the Facebook pages owned by the Macao Government were analyzed. Data were grouped into the prodromal, acute and chronic stages using Fink’s crisis management model, and qualitative content analysis was used to classify data into categories. The average values of the engagement (i.e., the numbers of emotions, comments and shares) were compared. RESULTS 1,664 posts from January 1st, 2020 to October 31st, 2020 were analyzed. The engagement was relatively low at the beginning and then surged in the acute stage, with a decreasing trend in the chronic stage. Information about latest updates, press conferences, community resilience and appreciation could maintain their engagement in the entire duration. Posts for controlling rumors attracted positive engagement and a high number of shares. The focuses of the public changed throughout the pandemic. CONCLUSIONS Government social media should be used with different focuses in different stages of the pandemic, for example, increasing vigilance and awareness in the prodromal stage, disseminating updates and seeking feedback in the acute stage, and focusing on mental health support and recovery policies in the chronic stage. Additionally, government social media can be an effective tool for controlling rumors, providing updates and fostering community engagement in massive public health crises.