Understanding the role of behaviour in modelling infectious disease spread Dr Dale Weston Research Fellow, Behavioural Science Research Team, Emergency Response Department Science & Technology, Health Protection Directorate, Public Health England
Background Mathematical modelling can reproduce observed spread of diseases (e.g., Silhol & Boëlle, 2011; Rvachev & Longini, 1985; Ferguson et al., 2003) S I R Planning responses to future infectious disease outbreaks which interventions might work and when? 2 Understanding the role of behaviour in modelling infectious disease spread
Traditional models typically assumed homogeneous behaviour (Frías-Martínez, Williamson, & Fríaz-Martínez, 2011) Models which allow for spontaneous, heterogeneous behaviour can substantially alter projected spread of infection (e.g., Epstein, Parker, Cummings & Hammond, 2008) But how and why does behaviour change? How is this currently modelled? 3 Understanding the role of behaviour in modelling infectious disease spread
Psychological Behaviour Change Literature 4 Extensive literature on behaviour change 83 theories identified (Michie et al., 2015) Application of Social Psychology to health promotion The Social Cure Relevance for understanding infectious disease epidemiology? Understanding the role of behaviour in modelling infectious disease spread
Aims To understand: (a) what behavioural mechanisms are already implicated in mathematical modelling, and; (b) which psychological health behaviour theories/ models are most applicable within an infectious disease modelling context Two reviews: 1. Review of the current role of human behaviour in the infectious disease modelling literature (Lead: Dale Weston) 2. Review of health behaviour theories applied in the context of infectious disease transmission (Lead: Athena Ip) Work is still ongoing interim findings/ conclusions 5 Understanding the role of behaviour in modelling infectious disease spread
Review 1 Search terms focused on: Human behaviour Mathematical modelling Infectious diseases Separate searches conducted on: 6 MEDLINE Embase PubMed (top-up search) Understanding the role of behaviour in modelling infectious disease spread
Medline; behavio*.ti,ab; 829344 results. Medline; BEHAVIOR/; 26977 results. Medline; BEHAVIOR AND BEHAVIOR MECHANISMS/; 0 results. Medline; BEHAVIORAL RESEARCH/; 2427 results. Medline; HEALTH BEHAVIOR/; 35794 results. Medline; PATIENT ACCEPTANCE OF HEALTH CARE/; 32289 results. Medline; Communicable-disease*.ti,ab; 6329 results. Medline; Infectious-disease*.ti,ab; 55396 results. Medline; transmissable-disease*.ti,ab; 6 results. Medline; (disease* adj3 transmiss*).ti,ab; 11471 results. Medline; DISEASE TRANSMISSION, INFECTIOUS/; 6242 results. Medline; COMMUNICABLE DISEASES/; 18013 results. Medline; (theoretic* adj3 model*).ti,ab; 21469 results. Medline; (mathematic* adj3 model*).ti,ab; 38369 results. Medline; (epidemi* adj3 model*).ti,ab; 4478 results. Medline; (econom* adj3 model*).ti,ab; 4191 results. Medline; (meta adj3 model*).ti,ab; 2297 results. Medline; (individual* adj3 based adj3 model*).ti,ab; 1508 results. Medline; MODELS, THEORETICAL/; 112019 results. 7 Understanding the role of behaviour in modelling infectious disease spread
Inclusion/ Exclusion Criteria 1. Focus on human-to-human infection 2. Focus on human infection prevention behaviour 3. Be explicitly focused on behaviour that originates from within the model 4. Must include a mathematical model or modelling component 5. Papers are published in peer reviewed academic journals 6. Papers must present a novel mathematical model 8 Understanding the role of behaviour in modelling infectious disease spread
Timeline of Papers 14 12 10 Number of papers 8 6 4 2 0 Year of publication 10 Understanding the role of behaviour in modelling infectious disease spread
Theoretical Background 73 papers DO provide literature in the introduction that relates in some way to behaviour: 60 50 Number of papers 40 30 20 10 0 Behaviour theory background Economics background Theoretical background cited Modelling background 11 Understanding the role of behaviour in modelling infectious disease spread
Commonly Applied Constructs Social Perceived adoption pressure; perceived social norms; social impact; behavioural transmission through social contact; imitation/ behavioural comparison; awareness Cognitive Perceived susceptibility; perceived severity; perceived benefits; prevalence; costs of un-altered behaviour; costs of altered behaviour; previous disease/ vaccination experience; perceived vaccine efficacy; vaccine/ disease memory Emotional Fear 12 Understanding the role of behaviour in modelling infectious disease spread
Social Constructs Commonly prevalence focused Can be model local or global Can be threshold structured Information or behaviour can be spread as if contagion (E.g., through close contacts in network/ on lattice) Social norms Parameter for injunctive norms Behavioural imitation as a function of payoff comparisons Neighbours/ randomly selected agent Vaccination free riding Payoff of strategy proportional to use in population Role modelling 13 Understanding the role of behaviour in modelling infectious disease spread
Some Observations Emphasis is on geographical clustering Little consideration of social networks that transcend this (e.g., social media networks?) Transmission of prevalence information Contingent upon visibility of conditions/ illnesses and social acceptability? Basic consideration of social norms Imitation (often payoff governed); single parameter for social pressure; game theoretic consideration of other agents behaviour Little consideration of continuum of influence Role of group leaders? 14 Understanding the role of behaviour in modelling infectious disease spread
Some Future Considerations Imitation/ behaviour could be structured by social grouping of contact Context-specific activation of identity Level of identification Social clustering not geographical? Identity Salience Both for transmission of information/ awareness and behaviour Improved social norm concept Group specific; interaction with identification? Influence of group leaders/ role models 15 Understanding the role of behaviour in modelling infectious disease spread
Summary Models including human behaviour are a relatively recent development Neglect emotional constructs (see Durham & Casman, 2012) Theoretical background is overwhelmingly economic or modelling focused Neglect psychological models of health behaviour change Incorporate a wide range of cognitive and social predictors of behaviour. BUT insufficient operationalisation of social considerations 16 Understanding the role of behaviour in modelling infectious disease spread
A broader issue? We recently conducted a review of reviews concerning common theories applied to preventative behaviour in infectious disease/ emergency situations. 12 included papers Focus on at least one of the following contexts: A/H1N1 Avian flu SARS Emergency preparedness The most commonly cited theories across these reviews were collated 17 Understanding the role of behaviour in modelling infectious disease spread
Commonly Cited Reviews Health Belief Model (55) Theory of Planned Behaviour (21) Social Cognitive Theory (18) Protection Motivation Theory (12) Transtheoretical Model (9) Extended Parallel Process Model (7) Theory of Reasoned Action (7) Diffusion of Innovation Theory (5) Precaution Adoption Process Model (4) PRECEDE-PROCEED Model (4) The Common Sense Model (2) 18 Understanding the role of behaviour in modelling infectious disease spread
Commonly Cited Reviews Health Belief Model (55) Theory of Planned Behaviour (21) Social Cognitive Theory (18) Protection Motivation Theory (12) Transtheoretical Model (9) Extended Parallel Process Model (7) Theory of Reasoned Action (7) Diffusion of Innovation Theory (5) Precaution Adoption Process Model (4) PRECEDE-PROCEED Model (4) The Common Sense Model (2) 19 Understanding the role of behaviour in modelling infectious disease spread
Conclusion Models including human behaviour are a relatively recent development Theoretical background is overwhelmingly economic or modelling focused Neglect psychological models of health behaviour change Do incorporate a wide range of cognitive and social predictors of behaviour However, the social constructs are relatively unsophisticated. Benefit to more complex modelling? A broader consideration? The vast majority of studies identified employed the cognitively-focused Health Belief Model. 20 Understanding the role of behaviour in modelling infectious disease spread
Acknowledgements Athena Ip Dr Richard Amlôt Dr Katharina Hauck Bioterrorism and Emerging Disease Analysis team, Emergency Response Department Science & Technology, Public Health England Department of Infectious Disease Epidemiology, Imperial College, London 21 Understanding the role of behaviour in modelling infectious disease spread
Thank you for listening. Any Questions? dale.weston@phe.gov.uk 22 Understanding the role of behaviour in modelling infectious disease spread