Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand.
We analyse data from the early epidemic of H1N1-2009 in New Zealand, and estimate the reproduction number R. We employ a renewal process which accounts for imported cases, illustrate some technical pitfalls, and propose a novel estimation method to address these pitfalls. Explicitly accounting for t...
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doaj-a95b05d0e3b34cc684e1ede019f9bba62020-11-24T21:35:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0165e1783510.1371/journal.pone.0017835Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand.Michael George RobertsHiroshi NishiuraWe analyse data from the early epidemic of H1N1-2009 in New Zealand, and estimate the reproduction number R. We employ a renewal process which accounts for imported cases, illustrate some technical pitfalls, and propose a novel estimation method to address these pitfalls. Explicitly accounting for the infection-age distribution of imported cases and for the delay in transmission dynamics due to international travel, R was estimated to be (95% confidence interval: 107,1.47). Hence we show that a previous study, which did not account for these factors, overestimated R. Our approach also permitted us to examine the infection-age at which secondary transmission occurs as a function of calendar time, demonstrating the downward bias during the beginning of the epidemic. These technical issues may compromise the usefulness of a well-known estimator of R--the inverse of the moment-generating function of the generation time given the intrinsic growth rate. Explicit modelling of the infection-age distribution among imported cases and the examination of the time dependency of the generation time play key roles in avoiding a biased estimate of R, especially when one only has data covering a short time interval during the early growth phase of the epidemic.http://europepmc.org/articles/PMC3102662?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Michael George Roberts Hiroshi Nishiura |
spellingShingle |
Michael George Roberts Hiroshi Nishiura Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. PLoS ONE |
author_facet |
Michael George Roberts Hiroshi Nishiura |
author_sort |
Michael George Roberts |
title |
Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. |
title_short |
Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. |
title_full |
Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. |
title_fullStr |
Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. |
title_full_unstemmed |
Early estimation of the reproduction number in the presence of imported cases: pandemic influenza H1N1-2009 in New Zealand. |
title_sort |
early estimation of the reproduction number in the presence of imported cases: pandemic influenza h1n1-2009 in new zealand. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2011-01-01 |
description |
We analyse data from the early epidemic of H1N1-2009 in New Zealand, and estimate the reproduction number R. We employ a renewal process which accounts for imported cases, illustrate some technical pitfalls, and propose a novel estimation method to address these pitfalls. Explicitly accounting for the infection-age distribution of imported cases and for the delay in transmission dynamics due to international travel, R was estimated to be (95% confidence interval: 107,1.47). Hence we show that a previous study, which did not account for these factors, overestimated R. Our approach also permitted us to examine the infection-age at which secondary transmission occurs as a function of calendar time, demonstrating the downward bias during the beginning of the epidemic. These technical issues may compromise the usefulness of a well-known estimator of R--the inverse of the moment-generating function of the generation time given the intrinsic growth rate. Explicit modelling of the infection-age distribution among imported cases and the examination of the time dependency of the generation time play key roles in avoiding a biased estimate of R, especially when one only has data covering a short time interval during the early growth phase of the epidemic. |
url |
http://europepmc.org/articles/PMC3102662?pdf=render |
work_keys_str_mv |
AT michaelgeorgeroberts earlyestimationofthereproductionnumberinthepresenceofimportedcasespandemicinfluenzah1n12009innewzealand AT hiroshinishiura earlyestimationofthereproductionnumberinthepresenceofimportedcasespandemicinfluenzah1n12009innewzealand |
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