[Paper Review] How many infections of COVID-19 there will be in the "Diamond Princess"-Predicted by a virus transmission model based on the simulation of crowd flow

Zhiming Fang, Zhongyi Huang+6 more|arXiv (Cornell University)|Feb 25, 2020

COVID-19 epidemiological studies12 references36 citations

TL;DR

The paper uses a crowd-flow based virus transmission model to simulate COVID-19 spread on the Diamond Princess and estimates 850–1009 infections, analyzing the impact of protective measures and timing.

ABSTRACT

Objectives: Simulate the transmission process of COVID-19 in a cruise ship, and then to judge how many infections there will be in the 3711 people in the "Diamond Princess" and analyze measures that could have prevented mass transmission. Methods: Based on the crowd flow model, the virus transmission rule between pedestrians is established, to simulate the spread of the virus caused by the close contact during pedestrians' daily activities on the cruise ship. Measurements and main results: Three types of simulation scenarios are designed, the Basic scenario focus on the process of virus transmission caused by a virus carrier and the effect of the personal protective measure against the virus. The condition that the original virus carriers had disembarked halfway and more and more people strengthen self-protection are considered in the Self-protection scenario, which would comparatively accord with the actual situation of "Diamond princess" cruise. Control scenario are set to simulate the effect of taking recommended or mandatory measures on virus transmission Conclusions: There are 850~1009 persons (with large probability) who have been infected with COVID-19 during the voyage of "Diamond Princess". The crowd infection percentage would be controlled effectively if the recommended or mandatory measures can be taken immediately during the alert phase of COVID-19 outbreaks.

Motivation & Objective

• Motivate assessment of COVID-19 transmission on a cruise ship to understand potential scale of outbreak.
• Estimate total infections among 3711 people on the Diamond Princess during the voyage.
• Analyze how personal protective measures and timely interventions could have reduced transmission.

Proposed method

• Develop a crowd-flow based virus transmission rule between pedestrians.
• Simulate virus spread during daily activities on the cruise ship under three scenarios.
• Include a Basic scenario focusing on a virus carrier and the effect of personal protection.
• Incorporate a Self-protection scenario reflecting early disembarkation and increased self-protection.
• Create a Control scenario to simulate effects of recommended or mandatory measures.

Experimental results

Research questions

• RQ1 How many infections would occur among the Diamond Princess occupants under the modeled transmission dynamics?
• RQ2 What is the impact of personal protective measures on limiting spread in the simulated environment?
• RQ3 How would earlier or mandatory interventions alter the outbreak outcome on the voyage?

Key findings

• Estimated infections: 850–1009 persons (with large probability) infected during the voyage.
• The crowd infection percentage can be controlled effectively if recommended or mandatory measures are implemented immediately during the outbreak alert phase.
• Scenarios show differing transmission dynamics depending on passenger behavior and protection levels.
• Disembarkation dynamics and heightened self-protection influence the observed spread in the Self-protection scenario.
• Protection measures can substantially mitigate mass transmission in the modeled setting.