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Research Article

Controlling Endemic Cholera with Oral Vaccines

  • Ira M Longini Jr. mail,

    To whom correspondence should be addressed. E-mail: longini@scharp.org

    Affiliations: Vaccine and Infectious Disease Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America, Department of Biostatistics, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, United States of America

    X
  • Azhar Nizam,

    Affiliation: Department of Biostatistics, The Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America

    X
  • Mohammad Ali,

    Affiliation: International Vaccine Institute, Seoul, Korea

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  • Mohammad Yunus,

    Affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh

    X
  • Neeta Shenvi,

    Affiliation: Department of Biostatistics, The Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America

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  • John D Clemens

    Affiliation: International Vaccine Institute, Seoul, Korea

    X
  • Published: November 27, 2007
  • DOI: 10.1371/journal.pmed.0040336

Reader Comments (1)

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Efficacy and Herd Protection of Oral Cholera Vaccine

Posted by plosmedicine on 31 Mar 2009 at 00:18 GMT

Author: Paul T Francis
Position: Associate Professor, Community Medicine
Institution: Amrita Institute of Medical Sciences, Cochin, India
E-mail: paultfrancis@gmail.com
Additional Authors: Nil
Submitted Date: December 13, 2007
Published Date: December 13, 2007
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

I read with interest the study on Oral Cholera Vaccine.
But the main conclusions of the study seems to be unbelievable.

Herd protection/Herd effect prevents disease in some of the unimmunised because of being 'surrounded' by immune persons who probably prevent spread of disease agent. This makes the actual protection in the community a shade more than what we expect from the vaccine efficacy.

However the conclusions from this study is unbelievable. A vaccine whose efficacy is moderate (about 70%) when given to 50% of the population reducing the disease in the unvaccinated by 89% seems to defy all immunology and epidemiology.

Even though it is a 'model' study I feel that this incredible phenomenon requires some explanation within what is known about Cholera epidemiology and immunology.

No competing interests declared.