PurposeIn a context of critical transition such as the COVID-19 pandemic, moral semantics take a prominent role as a form of self-description of society. However, they are not usually observed, but rather assumed as self-evident and necessarily “good.” The purpose of the article is to summarize the theory of morality from the social systems' perspective and illustrate with concrete examples the polemogenous nature of moral communication.Design/methodology/approachThis article presents an analysis of the role of morality in the context of the COVID-19 pandemic, from the perspective of Niklas Luhmann’s social systems theory. Applying the method of second-order observation, it describes three cases of moral semantics disseminated via mass media and social media, and it examines their connection with the structural situation of subsystems of society during the pandemic crisis (particularly healthcare, politics and science).FindingsSecond-order observation of moral communication demonstrates to be fruitful to describe the conditions and consequences in which moralization of communication occurs, particularly in a situation of critical transition around the healthcare crisis. The three examples examined, namely, the hero semantics directed to healthcare workers, the semantics of indiscipline and the controversies around pseudo-sciences and conspiracy theories, show how they are based on social attribution of esteem and disesteem, how they try to answer to troublesome situations and contradictions that seem difficult to cope, and how they are close related to the emergence of conflicts, even when they seem positive oriented and well intentioned.Originality/valueThis paper is an attempt to test the usefulness of Luhmann's theory of society to understand the ongoing COVID-19 crisis and particularly the role of moral communication in concrete examples.