Historically, infectious diseases have been responsible for the largest human death toll. Though we have achieved extraordinary technological advancement to contain disease spreads in the form of pharmaceutical interventions, the recent pandemic reminds us of the importance of nonpharmaceutical interventions (NPIs) based on social distancing, self-isolation, and vaccination. In an ever more interdependent world, large-scale behaviour changes will be crucial in preventing future outbreaks. Unfortunately, some of our instincts are not fine-tuned to guide us effectively through global health crises such as the COVID-19 pandemic. The invisibility of the threat and the remote consequences of our actions keep many of us from making individual choices that would lead to a greater collective good. 

In this regard, a fundamental challenge for the public health response is the generalised opposition to appropriate epidemic measures, which is sometimes fomented by the news media, influential people, extremist politicians, and rampant misinformation circulated online—a potential disorder of information brought on by an “infodemic”. The misunderstandings and mistrusts fuelled by misinformation can undermine effective public health measures and vaccination rollouts. However, little is known about the mechanism through which these potentially harmful messages propagate and how they, in turn, influence the behaviour of the population in opposing vaccine, mask-wearing, social distancing, and mobility restrictions, ultimately leading to higher levels of morbidity and mortality 

Research Objectives

Theoretical modelling and simulations have begun to explore the possible consequences of non-compliance behaviour on disease spread and mortality. Patel et al. used a decision analytical model to understand the importance of vaccination strategies and NPIs, including reduced mobility, school closure, and the use of face masks. The simulation outcome shows that removing NPIs while vaccines are distributed may result in substantial increases in infections, hospitalisations and mortality. Margraf et al. surveyed around 7,500 participants from eight countries and discovered a nearly tenfold difference in additional mortality for countries with low adherence than high adherence to NPIs. In a ground-breaking empirical study, Basellini et al. (the proposed supervisors of this project) leveraged digital-trace mobility data to examine the impact of reduced human mobility on excess mortality during the first wave of COVID-19 in the context of England and Wales. They demonstrate that the number of excess deaths could have been doubled in the absence of mobility restrictions. These initial studies paved the way for more systematic and causal investigation into how population behaviour affects the macro-level course of epidemics in terms of hospitalisation and mortality rates.

Despite the observable connection between behavioural change and epidemic outcomes, it is still unclear why populations have disparate responses to vaccination strategies and NPIs. At the micro level, an individual’s information intake and behaviour can be influenced by various sources, such as the physician, who represents the scientific community and voice of authority; the family and friends, who represent one’s social network and interaction in a geographically constrained scenario; and traditional and social media, with their various dimensions and ways of channelling information that can ultimately influence individual decisions. While the influence of physicians and peers has been widely investigated in the literature, how online information and misinformation affect behaviour in the real world remains understudied. Research predating this pandemic has shown how sentiments in online tweets about the influenza vaccine reflect the actual vaccine update and how Google Trends can predict disease outbreaks. The emergence of COVID-19 has spurred a number of small-scale studies (with a maximum of 2,000 observations) on how vaccine-related internet memes are connected to intentions to vaccinate and on how health misinformation influences individuals’ readiness to follow preventative measures. As new infectious diseases such as the recent Monkeypox continue to emerge, misleading and potentially harmful information about virus origin and vaccines is still being shared online. It is imperative to provide more systematic empirical evidence and a theoretical framework on the hypothesised relationships between online misinformation, real-world non-compliance behaviour, and epidemic outcomes.

By leveraging the available real-world observational data, new digital records on human interactions, and social science methodologies, this research project aims to advance the ongoing discussion on non-compliance behaviour with COVID-19 mitigation measures by empirically establishing the following two associations: the effect of public resistance to epidemic measures on disease spread, hospitalisation and excess mortality; and the effect of online misinformation on behavioural opposition to the epidemic measures. Additionally, the project attempts to develop a theoretical framework that incorporates behavioural and social science theories to understand the demographic, socioeconomic, and political determinants of non-compliance.