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The contribution of neighbours to an individual's risk of typhoid outcome

An individual's risk of infection from an infectious agent can depend on both the individual's own risk and protective factors and those of individuals in the same community. We hypothesize that an individual's exposure to an infectious agent is associated with the risks of infection...

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Autores principales: CHAO, D. L., PARK, J. K., MARKS, F., OCHIAI, R. L., LONGINI, I. M., HALLORAN, M. E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cambridge University Press 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4619120/
https://www.ncbi.nlm.nih.gov/pubmed/25936682
http://dx.doi.org/10.1017/S0950268815000692
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author CHAO, D. L.
PARK, J. K.
MARKS, F.
OCHIAI, R. L.
LONGINI, I. M.
HALLORAN, M. E.
author_facet CHAO, D. L.
PARK, J. K.
MARKS, F.
OCHIAI, R. L.
LONGINI, I. M.
HALLORAN, M. E.
author_sort CHAO, D. L.
collection PubMed
description An individual's risk of infection from an infectious agent can depend on both the individual's own risk and protective factors and those of individuals in the same community. We hypothesize that an individual's exposure to an infectious agent is associated with the risks of infection of those living nearby, whether their risks are modified by pharmaceutical interventions or by other factors, because of the potential for transmission from them. For example, unvaccinated individuals living in a highly vaccinated community can benefit from indirect protection, or living near more children in a typhoid-endemic region (where children are at highest risk) might result in more exposure to typhoid. We tested this hypothesis using data from a cluster-randomized typhoid vaccine trial. We first estimated each individual's relative risk of confirmed typhoid outcome using their vaccination status and age. We defined a new covariate, potential exposure, to be the sum of the relative risks of all who live within 100 m of each person. We found that potential exposure was significantly associated with an individual's typhoid outcome, and adjusting for potential exposure affected estimates of vaccine efficacy. We suggest that it is useful and feasible to adjust for spatially heterogeneous distributions of individual-level risk factors, but further work is required to develop and test such approaches.
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spelling pubmed-46191202015-12-01 The contribution of neighbours to an individual's risk of typhoid outcome CHAO, D. L. PARK, J. K. MARKS, F. OCHIAI, R. L. LONGINI, I. M. HALLORAN, M. E. Epidemiol Infect Original Papers An individual's risk of infection from an infectious agent can depend on both the individual's own risk and protective factors and those of individuals in the same community. We hypothesize that an individual's exposure to an infectious agent is associated with the risks of infection of those living nearby, whether their risks are modified by pharmaceutical interventions or by other factors, because of the potential for transmission from them. For example, unvaccinated individuals living in a highly vaccinated community can benefit from indirect protection, or living near more children in a typhoid-endemic region (where children are at highest risk) might result in more exposure to typhoid. We tested this hypothesis using data from a cluster-randomized typhoid vaccine trial. We first estimated each individual's relative risk of confirmed typhoid outcome using their vaccination status and age. We defined a new covariate, potential exposure, to be the sum of the relative risks of all who live within 100 m of each person. We found that potential exposure was significantly associated with an individual's typhoid outcome, and adjusting for potential exposure affected estimates of vaccine efficacy. We suggest that it is useful and feasible to adjust for spatially heterogeneous distributions of individual-level risk factors, but further work is required to develop and test such approaches. Cambridge University Press 2015-12 2015-05-04 /pmc/articles/PMC4619120/ /pubmed/25936682 http://dx.doi.org/10.1017/S0950268815000692 Text en © Cambridge University Press 2015 https://creativecommons.org/licenses/by/3.0/This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/3.0/ (https://creativecommons.org/licenses/by/3.0/) ), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Papers
CHAO, D. L.
PARK, J. K.
MARKS, F.
OCHIAI, R. L.
LONGINI, I. M.
HALLORAN, M. E.
The contribution of neighbours to an individual's risk of typhoid outcome
title The contribution of neighbours to an individual's risk of typhoid outcome
title_full The contribution of neighbours to an individual's risk of typhoid outcome
title_fullStr The contribution of neighbours to an individual's risk of typhoid outcome
title_full_unstemmed The contribution of neighbours to an individual's risk of typhoid outcome
title_short The contribution of neighbours to an individual's risk of typhoid outcome
title_sort contribution of neighbours to an individual's risk of typhoid outcome
topic Original Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4619120/
https://www.ncbi.nlm.nih.gov/pubmed/25936682
http://dx.doi.org/10.1017/S0950268815000692
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