Introduction: This study investigated influences of multimedia tweets on retweetablity during public health crises, in order to provide evidence for facilitating effective use of Twitter for health communication.

Method: Using the Twitter stream API, a total of 359,043 Zika-related tweets were collected for analysis.

Analysis: The sampled tweets were quantitatively analysed using descriptive statistics and chi-squared tests. For content analysis, subsets of the dataset were manually coded.

Results: 1) text tweets were sent out more frequently than multimedia tweets, but multimedia tweets had higher retweetability, 2) tweets by government, mainstream news media, and online news media were frequently retweeted, 3) images were often used for educational and informational (not news) tweets, and videos were used for educational and political purposes, 4) however, considering retweetability, highly retweeted images were for disseminating brief news, and highly retweeted video tweets were for disseminating informational or educational messages, and 5) ratios of non-U.S. agents were higher in multimedia retweets than text retweets.

Conclusion: The findings can help government and business practitioners to build their social media communication strategies in order to effectively select proper content and multimedia formats to enhance the impact of information sharing and communications during emergent health situations.