Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.

Could some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circ...

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Main Authors: Andrew F Read, Susan J Baigent, Claire Powers, Lydia B Kgosana, Luke Blackwell, Lorraine P Smith, David A Kennedy, Stephen W Walkden-Brown, Venugopal K Nair
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2015-07-01
Series:PLoS Biology
Online Access:https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1002198&type=printable
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author Andrew F Read
Susan J Baigent
Claire Powers
Lydia B Kgosana
Luke Blackwell
Lorraine P Smith
David A Kennedy
Stephen W Walkden-Brown
Venugopal K Nair
author_facet Andrew F Read
Susan J Baigent
Claire Powers
Lydia B Kgosana
Luke Blackwell
Lorraine P Smith
David A Kennedy
Stephen W Walkden-Brown
Venugopal K Nair
author_sort Andrew F Read
collection DOAJ
description Could some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Here we show experimentally that immunization of chickens against Marek's disease virus enhances the fitness of more virulent strains, making it possible for hyperpathogenic strains to transmit. Immunity elicited by direct vaccination or by maternal vaccination prolongs host survival but does not prevent infection, viral replication or transmission, thus extending the infectious periods of strains otherwise too lethal to persist. Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts.
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institution Kabale University
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language English
publishDate 2015-07-01
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spelling doaj-art-e50d438f0e7b491b88a1676fc6ae27a72025-08-20T03:46:42ZengPublic Library of Science (PLoS)PLoS Biology1544-91731545-78852015-07-01137e100219810.1371/journal.pbio.1002198Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.Andrew F ReadSusan J BaigentClaire PowersLydia B KgosanaLuke BlackwellLorraine P SmithDavid A KennedyStephen W Walkden-BrownVenugopal K NairCould some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Here we show experimentally that immunization of chickens against Marek's disease virus enhances the fitness of more virulent strains, making it possible for hyperpathogenic strains to transmit. Immunity elicited by direct vaccination or by maternal vaccination prolongs host survival but does not prevent infection, viral replication or transmission, thus extending the infectious periods of strains otherwise too lethal to persist. Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts.https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1002198&type=printable
spellingShingle Andrew F Read
Susan J Baigent
Claire Powers
Lydia B Kgosana
Luke Blackwell
Lorraine P Smith
David A Kennedy
Stephen W Walkden-Brown
Venugopal K Nair
Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
PLoS Biology
title Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
title_full Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
title_fullStr Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
title_full_unstemmed Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
title_short Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens.
title_sort imperfect vaccination can enhance the transmission of highly virulent pathogens
url https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1002198&type=printable
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