  Social media has been one of the main information consumption sources for the
public, allowing people to seek and spread information more quickly and easily.
However, the rise of various social media platforms also enables the
proliferation of online misinformation. In particular, misinformation in the
health domain has significant impacts on our society such as the COVID-19
infodemic. Therefore, health misinformation in social media has become an
emerging research direction that attracts increasing attention from researchers
of different disciplines. Compared to misinformation in other domains, the key
differences of health misinformation include the potential of causing actual
harm to humans' bodies and even lives, the hardness to identify for normal
people, and the deep connection with medical science. In addition, health
misinformation on social media has distinct characteristics from conventional
channels such as television on multiple dimensions including the generation,
dissemination, and consumption paradigms. Because of the uniqueness and
importance of combating health misinformation in social media, we conduct this
survey to further facilitate interdisciplinary research on this problem. In
this survey, we present a comprehensive review of existing research about
online health misinformation in different disciplines. Furthermore, we also
systematically organize the related literature from three perspectives:
characterization, detection, and intervention. Lastly, we conduct a deep
discussion on the pressing open issues of combating health misinformation in
social media and provide future directions for multidisciplinary researchers.
