This study delves into the risk and crisis communication strategies employed by the Portuguese Directorate-General of Health (DGS) throughout the COVID-19 pandemic and assesses their impact on audience engagement, aiming to elucidate how effective communication can bolster public safety and well-being during health crises. Employing a mixed-methods design, we conducted deductive and inductive content analysis of DGS Facebook’s posts alongside quantitative analysis of audience interactions, over a dataset of 539 posts, spanning the initial four months of the pandemic. We reveal the dominant themes of the DGS social media communication strategy and its effects on audience engagement. Three primary themes were identified: guidelines and prevention measures, information and updates, and awareness campaigns, together with twenty-one specific topics. Notably, posts focusing on hygiene practices, mask usage, and social distancing elicited substantial audience engagement, particularly in shares and comments. Situational reports and press conferences emerged as pivotal tools for disseminating timely information and upholding transparency. Emotion analysis uncovered distinct audience reactions across themes, with hygiene-related posts evoking predominantly positive emotions, however, press conferences and regulations prompted mixed responses, revealing anxiety, uncertainty, and heightened perceived risk. The heightened levels of emotional entropy in crisis communication themes highlight the necessity for nuanced communication tactics to handle critical audience attitudes effectively, even though the adopted social media communication strategy is diverse and, in most themes, efficient.