This article analyses the conversations on Twitter related to the World Health Organization (WHO). We collect the text of the discussions as well as the metadata associated with each tweet. Our dataset is exhaustive as it includes all the tweets produced by WHO. Likes, retweets, and replies capture the level of engagement. The goal is to quantify the balance of likes, retweets, and replies, also known as “ratios”, and study their dynamics as proxy for the collective engagement in response to WHO’s communications. Our results demonstrate a higher engagement of the public receiving the information pushed by WHO. This engagement translates into a more balanced reaction with still a more likely favorable opinion vis-à-vis WHO, but with also more challenges. This protocol based on quantitative measures to serve as a proxy to the legitimacy concept seems to hold its promises. In particular, we also perform a simple sentiment analysis to check the robustness of our conclusions.