While the precise conceptualization of the term misinformation remains a subject of debate, the current entry defines misinformation as any type of information which is misleading or false, regardless of intent. The COVID-19 pandemic has seen the rapid and widespread sharing of misinformation on a global scale, which has had detrimental effects on containment efforts and public health. This entry offers psychological insights to better our understanding of what makes people susceptible to believing and sharing misinformation and how this can inform interventions aimed at tackling the issue.
December 2019 saw the emergence of SARS-CoV-2, a novel virus causing the coronavirus disease (COVID-19), which spread aggressively and rapidly across the globe. By 11 March 2020, the World Health Organization (WHO) had declared the outbreak a pandemic, and by 18 September 2021, there were over 226 million cases of COVID-19 and 4.7 million deaths reported worldwide 
. This global crisis was paralleled by the widespread sharing of both scientific and non-scientific information surrounding COVID-19 across multiple media channels. For the first time in history, social media and technology were being used on a huge scale by public health authorities and other institutions to keep people informed, safe, and connected. Social media and technology played an essential role in the response to the pandemic, for instance, through the implementation and promotion of public health measures, the tracking and mapping of symptoms, as well as the prediction of outbreaks in real-time. At the same time, however, this same technology also facilitated the overabundant spreading of information from uninformed sources, not all of which were accurate and reliable. The global scale of the pandemic amplified this spreading as people urgently sought out and shared information in an effort to protect themselves, their families, and their communities against the virus 
On 15 February 2020, T.A. Ghebreyesus, the Director-General of WHO, announced the concern that the omnipresence and overabundance of often conflicting and inaccurate information posed a significant challenge for public health and was jeopardizing the response to the pandemic 
. WHO declared that the world was facing what they termed an infodemic; “an overabundance of information, some accurate and some not, that makes it hard for people to find trustworthy sources and reliable guidance when they need it” 
(p. 2). The COVID-19 infodemic saw the spread of information concerning the origin and cause of the virus and disease, the transmission of the virus and symptoms of the disease, available prophylactics, treatments and cures, and the impact and efficacy of interventions by public health authorities or other institutions 
. Amongst this information was fake news, misinformation, disinformation, and conspiracy theories, which caused many to mistrust reliable sources of information and develop a distorted risk perception of the virus 
. Due to this, people were less likely to adopt preventative public health behaviors, which had an adverse effect on the implementation and efficacy of containment strategies 
The management of the infodemic was soon publicly recognized by WHO as a crucial part of the response to COVID-19 
. On 29 June 2020, WHO held its first global infodemiology conference 
, which led to the publication of the WHO Public Health Research Agenda for Managing Infodemics 
. In this publication, WHO identified a need for research in the field of psychology to identify factors that make people more likely to share or believe inaccurate information 
. Understanding these factors can inform and enhance the development of innovative and creative interventions aimed at infodemic management.
This entry begins with a description of what constitutes fake news, misinformation, and disinformation, explores cases from the COVID-19 infodemic and considers the effect this has had on the societal response to the pandemic. It then goes on to explore the main psychological factors that have been found to play a role in the believability of misinformation and the role of sharing behavior. The entry ends with a description of interventions aimed at addressing misinformation.