WeChat has become the primary channel to obtain information on COVID-19. Many subscribe the official accounts of CDC, as it provides authentic and authoritative information about the pandemic. However, few studies have explored information published on the CDC’s account during the pandemic.

    To address this issue, this study uses topic modeling method in computational communication to conduct a case study of the WeChat official account “Shandong CDC” and introduces Kiousis’s definition of “media attention” in the agenda setting theory, operationalizing the concept of media attention into the amount of content published.

    We crawled the titles of all articles published by Shandong CDC’s WeChat official account from 19 December 2019 to 25 March 2022, and obtained a dataset of 3,726 articles titles. Biterm Topic Model was used to analyze the 3,726 article titles, as the titles of WeChat articles are short texts and the traditional LDA subject model is suitable for long text analysis.

    We identified four topics for information dissemination on the Shandong CDC’s WeChat official account during the pandemic, and visualized the subjects using PyLDAvis. Topic 1 is updates on the pandemic, including confirmed cases, risk area summaries and flow information. Topic 2 is information on health literacy improvement and personal protection guidelines for COVID-19. Topic 3 is education on the history of the Communist Party and it's practical work. Topic 4 is the knowledge dissemination of COVID-19 vaccine and the call for vaccination.

    Topic heatmap for time series was create. We found that Shandong CDC continues to focus on health literacy improvements and personal protection guidelines; while its attention to other topics was constantly flowing.

    Shandong CDC's attention to the pandemic fluctuated with the severity of the pandemic in Shandong Province, especially in March 2022, when the pandemic worsened in Shandong and the number of articles on topic 1 reached a peak; during the period of mass popularization of the vaccination (March 2021 to July 2021), Shandong CDC's account paid key attention towards the topic.

    Topic 3 was messages with Chinese characteristics. In addition to the celebration of the 100th anniversary of the founding of the Communist Party of China in July 2021, when media attention peaked, there were ongoing educational messages on learning about the history of the Party and examples of the service to people from August 2021 to January 2022.

    During major public health events, the population relies heavily on official channels for information acquisition. Shandong CDC's attention to information related to the pandemic (Topic 1, 2 and 4) accounted for 74.1% of all attention combined. The CDC filled the public's health information gap with extensive media attention and contents of COVID-19 updates, vaccination and protection knowledge.

    In addition to its attributes as a health information distributor, the Shandong CDC's WeChat official account paid 25.9% of its attention to political construction. As an infrastructure for health information dissemination, the CDC's WeChat official account takes on two major functions of public health promotion and political propaganda, which is a unique feature found in this study.