What you just saw
The epidemic curve itself is familiar — rise, peak, fall. The new thing here is the horizontal capacity line. When infection demand crosses the bed or ICU line, the excess patients cannot be treated at the full standard of care, and mortality for that cohort jumps sharply. The total mortality is not just the R₀ of the disease — it is R₀ plus the peak-to-capacity ratio.
The science behind it
Simple SEIR models treat mortality as a fixed rate per infected case. Real-world hospital data from COVID-19 (and earlier from H1N1 and SARS-CoV-1) show mortality as a function of local ICU utilization: once you pass ~90% ICU occupancy, case-fatality climbs nonlinearly. This simulator captures the mechanism — healthcare capacity as a threshold that converts infection surge into excess mortality.
Try these experiments
1. Flattened curve
Settings: r0=1.3 total_beds=500
What to look for: Long epidemic, never exceeds capacity. Mortality stays at baseline.
2. Overwhelmed
Settings: r0=3.0 total_icu=50
What to look for: ICU saturates at the peak. Excess mortality visible as a clear step-up on the death curve.
3. Surge capacity
Settings: r0=3.0 total_icu=200
What to look for: Same epidemic, 4× ICU — mortality drops dramatically. Capacity planning matters enormously.
Run this at 100x scale
Hospital capacity runs in your browser up to 5,000 population agents. With SimLab, the same model runs on GPU at 10M+ population, with ensemble parameter sweeps and publication-ready output.
from scirouter import SciRouter
client = SciRouter(api_key="sk-sci-...")
result = client.simulation.run(
model="hospital",
params={"population": 1_000_000, "r0": 2.5,
"total_beds": 50_000, "total_icu": 5_000},
steps=365, seed=42,
)
print(result.metrics["excess_mortality"])Related simulations
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Frequently asked questions
How do I think about this for real surge planning?›
This simulator is a demonstration of the dynamic, not a planning tool. Real hospital capacity models (like the IHME model during COVID) use actual demographic data, hospital-specific admission rates, and ICU staffing ratios — not a toy SEIR.
What's the difference from the SEIR simulator?›
The SEIR simulator tracks infection dynamics. This simulator adds hospital beds and ICUs as finite resources, so you see not just how many get sick, but how many get treated — and how many don't.