2022 ESA Annual Meeting (August 14 - 19)

COS 136-4 Awareness-based behavior and disease dynamics in a split population

8:45 AM-9:00 AM
515A
Mallory Harris, Stanford;Erin Mordecai,Stanford University;
Background/Question/Methods

During infectious disease outbreaks, individuals may adopt protective measures like vaccination and physical distancing in response to awareness of disease impacts. Prior work showed how feedback between epidemic intensity and awareness-based behavioral changes can shape disease dynamics (e.g., producing plateaus and oscillations). These models often overlook the effects of social divisions, where population subgroups have different levels of vulnerability and respond more to the disease’s effects within their own group. We hypothesize that socially divided awareness-based behavior could fundamentally alter epidemic dynamics and shift disease burden between groups. We develop compartmental models of disease transmission in a population split in two groups where protective measures are adopted based on awareness of recent disease-linked mortality. We simulate different scenarios to explore the impact of awareness separation (relatively greater in- versus out-group awareness). We ask: (1) How do separation in awareness and mixing interact to widen or reduce disparities between groups in epidemic shape and size? (2) How does awareness-based behavior in a split population affect long-term dynamics? (3) When groups have different propensities to adopt protective behavior, how does relative disease burden in each group shift? (4) How does disease burden after vaccine introduction vary with vaccine efficacy and awareness separation?

Results/Conclusions

Social division and awareness separation can dramatically impact protective measure adoption and disease dynamics. The importance of awareness separation increases with mixing separation (i.e., reduced contact between groups). Uniform awareness across groups increases the relative disease burden in the group where the pathogen is introduced by allowing the second group to proactively build protection in response to awareness of the emerging epidemic. Separated awareness leads to similar epidemic shapes in both groups because the second group is less aware of the pathogen’s emergence. As protective behavior diminishes over time with fatigue, additional epidemic peaks may occur. Later peaks in the second group can exceed the initial wave in size if awareness separation is low because many individuals remain susceptible. Awareness separation’s impacts are modulated by between-group differences in protective measure uptake and efficacy. More effective vaccine may indirectly lead to more infections by reducing perceived risk of infection and vaccine uptake. When awareness is separated, the group with the higher fatality rate will have greater vaccine uptake, reducing between-group disparities in mortality while producing a difference in infections. Characterizing awareness separation empirically and understanding how it interacts with social divisions could guide more accurate disease modeling and effective policy interventions.