SEATTLE, Nov. 26 /PRNewswire/ -- Endemic cholera, a potentially fatal
diarrheal disease found in the world's most impoverished countries, could
be effectively controlled by orally vaccinating half of the affected
populations once every two years for only pennies per dose, according to
new findings by an international team of researchers led by Ira M. Longini
Jr., Ph.D., a biostatistician in the Vaccine and Infectious Disease
Institute at Fred Hutchinson Cancer Research Center in Seattle. Longini and
colleagues will report their findings online Nov. 27 in PLoS Medicine.
While oral cholera vaccines have been available to protect travelers
for more than a decade, they have not been used for widespread control of
the disease in cholera-prone (endemic) regions in part because their
protective potential has been underestimated. In fact, using a computer
simulation model based on data from a large-scale cholera-vaccine trial
involving 200,000 people in Matlab, Bangladesh, Longini and colleagues
suggest that internationally licensed, killed whole-cell cholera vaccines
(OCVs) may be highly effective in controlling cholera when given via mass
immunization.
Longini and colleagues estimate that cholera cases could be reduced
nearly 90 percent among the unvaccinated if just 50 percent of the
population received an oral vaccination biannually. Vaccinating just 30
percent of the population every two years would achieve an overall cholera
reduction rate of 76 percent. In populations with less experience with
cholera than Matlab, at least 70 percent of the population would need to be
vaccinated to control the disease.
"This is the first scientific work that shows how we could control
cholera on a global level," said Longini, also a professor of biostatistics
at the University of Washington School of Public Health and Community
Medicine. "Once you get up to about 50 percent of the population
vaccinated, you can drive the epidemic into practically nothing."
Endemic cholera is a bacterial infection of the small intestine that
causes acute, watery diarrhea. If untreated, it can lead to potentially
fatal dehydration. Although advances in rehydration therapy have made
cholera a treatable disease in areas with sufficient medical care, it
remains a fatal condition among the world's most impoverished populations.
The disease is caused by ingesting food or water contaminated with a
comma-shaped bacterium called Vibrio cholerae.
Co-authors on the paper included researchers from Emory University in
Atlanta; the International Vaccine Institute in Seoul, Korea; and the
International Centre for Diarrhoeal Disease Research in Bangladesh.
"These important findings stem from the recent recognition that oral
vaccines against cholera confer herd protection -- protection of
nonvaccinated neighbors of vaccinated persons," said John Clemens, M.D.,
director-general of the International Vaccine Institute and paper
co-author. "I believe this study will have an impact on the public-health
community's approach to controlling cholera," he said.
The research was supported by the Diseases of the Most Impoverished
(DOMI) Program of the Bill & Melinda Gates Foundation, a grant from the
National Institute of General Medical Sciences Models of Infectious Disease
Agent Study (MIDAS), and the U.S. National Institute of Allergy and
Infectious Diseases.
At Fred Hutchinson Cancer Research Center, our interdisciplinary teams
of world-renowned scientists and humanitarians work together to prevent,
diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers,
including three Nobel laureates, bring a relentless pursuit and passion for
health, knowledge and hope to their work and to the world. For more
information, please visit fhcrc.org.
PLoS Medicine is an open-access journal. Everything it publishes is
freely available for anyone to read, download, distribute and re-use. Below
is a link to the PLoS Medicine paper "Controlling endemic cholera with oral
vaccines" by Longini and colleagues:
http://medicine.plosjournals.org/perlserv/?request=get-
document&doi=10.1371/journal.pmed.0040336
CONTACT
Kristen Woodward
(206) 667-5095
kwoodwar@fhcrc.org
SOURCE Fred Hutchinson Cancer Research Center
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Related links:
http://www.fhcrc.org
CONTACT:
Kristen Woodward of Fred Hutchinson Cancer
Research Center, +1-206-667-5095, kwoodwar@fhcrc.org
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