The spread and control of norovirus outbreaks among hospitals in a region: a simulation model.
BACKGROUND
Because hospitals in a region are connected via patient sharing, a norovirus outbreak in one hospital may spread to others.


METHODS
We utilized our Regional Healthcare Ecosystem Analyst software to generate an agent-based model of all the acute care facilities in Orange County (OC), California and simulated various norovirus outbreaks in different locations, both with and without contact precautions.


RESULTS
At the lower end of norovirus reproductive rate (R0) estimates (1.64), an outbreak tended to remain confined to the originating hospital (≤6.1% probability of spread). However, at the higher end of R0 (3.74), an outbreak spread 4.1%-17.5% of the time to almost all other OC hospitals within 30 days, regardless of the originating hospital. Implementing contact precautions for all symptomatic cases reduced the probability of spread to other hospitals within 30 days and the total number of cases countywide, but not the number of other hospitals seeing norovirus cases.


CONCLUSIONS
A single norovirus outbreak can continue to percolate throughout a system of different hospitals for several months and appear as a series of unrelated outbreaks, highlighting the need for hospitals within a region to more aggressively and cooperatively track and control an initial outbreak.
Public Health Computational and Operations Research (PHICOR) , Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland ; Department of Industrial Engineering.
Sarah M
SM
Bartsch
University of California School of Medicine , Irvine, California.
Susan S
SS
Huang
Center for Simulation and Modeling , University of Pittsburgh , Pittsburgh, Pennsylvania.
Kim F
KF
Wong
Harvard Medical School and Harvard Pilgrim Health Care Institute , Boston, Massachusetts.
Taliser R
TR
Avery
Public Health Computational and Operations Research (PHICOR) , Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland.
Bruce Y
BY
Lee
hospitals; intervention; norovirus; outbreak