Building Ventilation as an Effective Disease Intervention Strategy in a Dense Indoor Contact Network in an Ideal City.

Xiaolei Gao,Hao Lei,Yuguo Li,Pengcheng Xu,Benjamin J Cowling,Jianjian Wei,Jeffrey Shaman

doi:10.1371/journal.pone.0162481

Abstract

Emerging diseases may spread rapidly through dense and large urban contact networks, especially they are transmitted by the airborne route, before new vaccines can be made available. Airborne diseases may spread rapidly as people visit different indoor environments and are in frequent contact with others. We constructed a simple indoor contact model for an ideal city with 7 million people and 3 million indoor spaces, and estimated the probability and duration of contact between any two individuals during one day. To do this, we used data from actual censuses, social behavior surveys, building surveys, and ventilation measurements in Hong Kong to define eight population groups and seven indoor location groups. Our indoor contact model was integrated with an existing epidemiological Susceptible, Exposed, Infectious, and Recovered (SEIR) model to estimate disease spread and with the Wells-Riley equation to calculate local infection risks, resulting in an integrated indoor transmission network model. This model was used to estimate the probability of an infected individual infecting others in the city and to study the disease transmission dynamics. We predicted the infection probability of each sub-population under different ventilation systems in each location type in the case of a hypothetical airborne disease outbreak, which is assumed to have the same natural history and infectiousness as smallpox. We compared the effectiveness of controlling ventilation in each location type with other intervention strategies. We conclude that increasing building ventilation rates using methods such as natural ventilation in classrooms, offices, and homes is a relatively effective strategy for airborne diseases in a large city.

Highlights

Infectious disease epidemics such as the 2003 SARS epidemic, the 2009 H1N1 pandemic, and the 2015 MERS epidemic are a threat to public health
Building ventilation is known to be effective for reducing the spread of airborne diseases such as tuberculosis, SARS, smallpox, chicken pox, and influenza in single indoor environments [8,9,10,11,12], but has not been studied at the community level
Our model produced a bipartite graph with two types of vertices, people and location

Summary

Introduction

Infectious disease epidemics such as the 2003 SARS epidemic, the 2009 H1N1 pandemic, and the 2015 MERS epidemic are a threat to public health. Building ventilation is known to be effective for reducing the spread of airborne diseases such as tuberculosis, SARS, smallpox, chicken pox, and influenza in single indoor environments [8,9,10,11,12], but has not been studied at the community level. Ventilation intervention decreases transmission probability by directing the flow of airborne infectious agents away from susceptible persons and/or by removing infectious agents from room air. Because it relies less on individual compliance, ventilation has an advantage over other non-pharmaceutical interventions (e.g., hand washing or mask use). Is ventilation as effective at the community level as other interventions?

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