The Western Africa Ebola virus disease epidemic exhibits both global exponential and local polynomial growth rates

Gerardo Chowell, Cécile Viboud, James M. Hyman, Lone Simonsen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

Background:
While many infectious disease epidemics are initially characterized by an exponential growth in time, we show that district-level
Ebola virus disease (EVD) outbreaks in West Africa follow slower polynomial-based growth kinetics over several generations of
the disease.
Methods:
We analyzed epidemic growth patterns at three different spatial scales (regional, national, and subnational) of the Ebola virus
disease epidemic in Guinea, Sierra Leone and Liberia by compiling publicly available weekly time series of reported EVD case
numbers from the patient database available from the World Health Organization website for the period 05-Jan to 17-Dec 2014.
Results:
We found significant differences in the growth patterns of EVD cases at the scale of the country, district, and other subnational
administrative divisions. The national cumulative curves of EVD cases in Guinea, Sierra Leone, and Liberia show periods of
approximate exponential growth. In contrast, local epidemics are asynchronous and exhibit slow growth patterns during 3 or
more EVD generations, which can be better approximated by a polynomial than an exponential function.
Conclusions:
The slower than expected growth pattern of local EVD outbreaks could result from a variety of factors, including behavior
changes, success of control interventions, or intrinsic features of the disease such as a high level of clustering. Quantifying the
contribution of each of these factors could help refine estimates of final epidemic size and the relative impact of different
mitigation efforts in current and future EVD outbreaks.
OriginalsprogEngelsk
TidsskriftPlos Outbreaks
Vol/bind7
StatusUdgivet - 2015
Udgivet eksterntJa

Citer dette

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title = "The Western Africa Ebola virus disease epidemic exhibits both global exponential and local polynomial growth rates",
abstract = "Background:While many infectious disease epidemics are initially characterized by an exponential growth in time, we show that district-levelEbola virus disease (EVD) outbreaks in West Africa follow slower polynomial-based growth kinetics over several generations ofthe disease.Methods:We analyzed epidemic growth patterns at three different spatial scales (regional, national, and subnational) of the Ebola virusdisease epidemic in Guinea, Sierra Leone and Liberia by compiling publicly available weekly time series of reported EVD casenumbers from the patient database available from the World Health Organization website for the period 05-Jan to 17-Dec 2014.Results:We found significant differences in the growth patterns of EVD cases at the scale of the country, district, and other subnationaladministrative divisions. The national cumulative curves of EVD cases in Guinea, Sierra Leone, and Liberia show periods ofapproximate exponential growth. In contrast, local epidemics are asynchronous and exhibit slow growth patterns during 3 ormore EVD generations, which can be better approximated by a polynomial than an exponential function.Conclusions:The slower than expected growth pattern of local EVD outbreaks could result from a variety of factors, including behaviorchanges, success of control interventions, or intrinsic features of the disease such as a high level of clustering. Quantifying thecontribution of each of these factors could help refine estimates of final epidemic size and the relative impact of differentmitigation efforts in current and future EVD outbreaks.",
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The Western Africa Ebola virus disease epidemic exhibits both global exponential and local polynomial growth rates. / Chowell, Gerardo; Viboud, Cécile; Hyman, James M.; Simonsen, Lone.

I: Plos Outbreaks, Bind 7, 2015.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - The Western Africa Ebola virus disease epidemic exhibits both global exponential and local polynomial growth rates

AU - Chowell, Gerardo

AU - Viboud, Cécile

AU - Hyman, James M.

AU - Simonsen, Lone

PY - 2015

Y1 - 2015

N2 - Background:While many infectious disease epidemics are initially characterized by an exponential growth in time, we show that district-levelEbola virus disease (EVD) outbreaks in West Africa follow slower polynomial-based growth kinetics over several generations ofthe disease.Methods:We analyzed epidemic growth patterns at three different spatial scales (regional, national, and subnational) of the Ebola virusdisease epidemic in Guinea, Sierra Leone and Liberia by compiling publicly available weekly time series of reported EVD casenumbers from the patient database available from the World Health Organization website for the period 05-Jan to 17-Dec 2014.Results:We found significant differences in the growth patterns of EVD cases at the scale of the country, district, and other subnationaladministrative divisions. The national cumulative curves of EVD cases in Guinea, Sierra Leone, and Liberia show periods ofapproximate exponential growth. In contrast, local epidemics are asynchronous and exhibit slow growth patterns during 3 ormore EVD generations, which can be better approximated by a polynomial than an exponential function.Conclusions:The slower than expected growth pattern of local EVD outbreaks could result from a variety of factors, including behaviorchanges, success of control interventions, or intrinsic features of the disease such as a high level of clustering. Quantifying thecontribution of each of these factors could help refine estimates of final epidemic size and the relative impact of differentmitigation efforts in current and future EVD outbreaks.

AB - Background:While many infectious disease epidemics are initially characterized by an exponential growth in time, we show that district-levelEbola virus disease (EVD) outbreaks in West Africa follow slower polynomial-based growth kinetics over several generations ofthe disease.Methods:We analyzed epidemic growth patterns at three different spatial scales (regional, national, and subnational) of the Ebola virusdisease epidemic in Guinea, Sierra Leone and Liberia by compiling publicly available weekly time series of reported EVD casenumbers from the patient database available from the World Health Organization website for the period 05-Jan to 17-Dec 2014.Results:We found significant differences in the growth patterns of EVD cases at the scale of the country, district, and other subnationaladministrative divisions. The national cumulative curves of EVD cases in Guinea, Sierra Leone, and Liberia show periods ofapproximate exponential growth. In contrast, local epidemics are asynchronous and exhibit slow growth patterns during 3 ormore EVD generations, which can be better approximated by a polynomial than an exponential function.Conclusions:The slower than expected growth pattern of local EVD outbreaks could result from a variety of factors, including behaviorchanges, success of control interventions, or intrinsic features of the disease such as a high level of clustering. Quantifying thecontribution of each of these factors could help refine estimates of final epidemic size and the relative impact of differentmitigation efforts in current and future EVD outbreaks.

M3 - Journal article

VL - 7

JO - Plos Outbreaks

JF - Plos Outbreaks

ER -