PurposeAlthough crisis communication via social media has engaged academia's attention during the disease outbreak, information value for preventive behaviors is inadequately studied. The purpose of this paper is to cast light on how to strengthen the uptake of older people's coronavirus disease 2019 (COVID-19) behavioral outcomes due to information value and perceived threat through social media.Design/methodology/approachThis study designs a survey and applies structural equation modeling to examine a research framework. A sample comprises 334 Vietnamese older participants who have utilized social media.FindingsThe results illustrate that preventive behaviors are determined by perceived threat (i.e. severity and susceptibility). Furthermore, older people heighten risk perceptions based on information characteristics, including information relevance, informative support and source credibility. Lastly, information relevance is a strong predictor of source credibility.Practical implicationsThe findings assist practitioners to enhance crisis communication effectiveness via social media by imparting valuable information to the public. Moreover, this paper offers overarching guidelines on the improvement in credibility with creators, risk consciousness and preventive behaviors.Originality/valueAlthough earlier studies focused attentiveness on the power of social media for raising threat perceptions, this work seems the first to unveil informative motives for perceived COVID-19 threat across older individuals, which subsequently presents plausible reasons for behavioral disclosure, including facemask-wearing, hand-washing and social distancing.