SISMID 2026 · Pre-session materials 2
Spatial and Metapopulation Modeling 2
Please complete all materials below before your first synchronous session.
The materials on this page should be reviewed before your live lab sessions on June 22 and June 23. Work through the videos, readings, and problem sets at your own pace.
Pre-session materials — Page 2
Reading Activity after Lecture 3
Format: Reading + Reflection Exercise | Time: 30 minutes | Best timing: After Lecture 3
Pre-Reading Context
This paper addresses a critical question that will become central to your Lab 3 work: When people or animals move between locations, does it matter WHO specifically is moving, or can we just track the total numbers?
Key Question to Keep in Mind: As you read, consider how this finding might change the way we interpret mobility data and build disease models.
Reading Strategy
The Central Problem (Introduction + Figure 1)
- What are the three different ways of modeling movement between populations?
- Why might individual identity matter for disease spread?
Key Findings (Results section + Figures 1–2)
- How much difference does individual identity make in disease spread speed?
- Which diseases/scenarios show the biggest effects?
Real-World Applications (UK examples)
- How do the findings apply to both human commuting and cattle movement?
Reading Tips
- Skip the heavy mathematical details in the Materials and Methods section on first read
- Focus on the figures — they tell the main story
- Pay special attention to the commuter vs. random mover comparisons
Reflection Questions
1. What is the fundamental difference between the three movement models described in this paper?
- Kernel transmission
- Random movers
- Individual identity (commuters/cattle with fixed patterns)
Hint: Think about whether the same individuals always travel the same routes vs. different individuals traveling randomly.
2. The authors find that ignoring individual identity results in an overestimation of epidemic spread by approximately 20%. Is this a big deal or a small detail? Justify your answer.
- Policy implications for intervention timing
- Resource allocation for outbreak response
- Public confidence in model predictions
3. Give three examples from your own life where your movement patterns are more like “commuters” (fixed/regular) vs. “random movers.”
Commuter-like (Fixed Pattern)
Example 1:
Example 2:
Example 3:
Random Mover-like
Example 1:
Example 2:
Example 3:
Why does this distinction matter for disease spread?
4. The paper focuses on Great Britain. How generalizable do you think these findings are?
- Different transportation systems (US vs. UK vs. developing countries)
- Different cultural patterns of mobility
- Different types of infectious diseases
- Different animal/livestock systems
Connection to Course Labs
- Lab 1 Bridge: How might the mobility data you analyzed mask important individual-level patterns?
- Lab 2 Preview: Should importation risk calculations account for whether travelers are regular commuters vs. random visitors?
- Lab 3 Preparation: What metapopulation modeling choices will you need to make about individual vs. aggregate movement?
Pre-Course Work Lecture 4
Travel restrictions and the role of age in spatial transmission. (Approx. 47 minutes of video content.)
Reading Activity after Lecture 4
Format: Reading + Reflection Exercise | Time: 30 minutes | Best timing: After Lecture 4
Pre-Reading Context
These two studies investigate the same fundamental question using different approaches: How do regular school holidays (particularly winter breaks) affect the timing and severity of influenza epidemics?
Key Question to Keep in Mind: As you read, consider how these findings might inform public health policy decisions about school calendar timing and emergency school closures.
Reading Strategy
Study 1: De Luca et al. (Belgium Study)
- Calendar Experiment: How do they test the impact of different holiday periods? Which holidays have the biggest impact and why?
- Mechanisms (Figure 3): What’s the difference between “mixing changes” and “travel changes” models? How do weekends vs. holidays affect transmission?
- Policy Implications (Figure 4 + Discussion): What happens when they extend Christmas holidays? How does epidemic timing interact with holiday timing?
Study 2: Ewing et al. (US Study)
- The Holiday Effect: How do winter holidays change influenza transmission patterns? What’s the difference between contact changes vs. travel changes?
- Age-Specific Impacts (Figure 2): How do holidays affect children vs. adults differently? Why does the relative risk shift toward adults during holidays?
- Modeling Approach: How do they isolate the effects of school closure vs. travel changes?
Cross-Study Comparison
- How do the US and Belgium findings compare?
- What methodological differences might explain any discrepancies?
Reflection Questions
1. Both studies conclude that contact pattern changes (not travel changes) drive the holiday effect on influenza. How do they each demonstrate this conclusion?
Compare their experimental approaches. What does this consistency across different countries and methods tell us?
2. Ewing et al. found that disease risk shifts toward adults during holidays. What mechanism explains this pattern?
- Why do children normally drive influenza transmission?
- What changes during school holidays?
- How might this affect vaccination strategies during holiday periods?
3. De Luca et al. test different holiday periods and find Christmas holidays have the largest impact. Why might this be?
- Epidemic timing in temperate regions
- Duration of different school breaks
- The interaction between epidemic growth phase and intervention timing
4. Both studies focus on “regular” school closure (planned holidays). How might their findings apply to pandemic school closures?
- Planned holidays with normal social activities
- Emergency closures during an active outbreak
- Compliance and behavioral differences
- Duration and implementation challenges
5. If you were a public health official, how might you use these findings to design better pandemic preparedness strategies?
- School calendar timing recommendations
- Targeted interventions during natural holiday periods
- Age-specific vaccination campaigns
- Communication strategies for different demographic groups
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