Good vaccine wrong. A recent polio outbreak was linked to a vaccine of virus that became contagious.
a vaccine to protect children against polio have instigated a recent outbreak of the disease in the Dominican Republic and Haiti - the first outbreak of polio in the Western Hemisphere in over 9 years. This is the first reliable report that a polio-strength vaccine strain can be returned to a virulent and contagious spread. A mass vaccination campaign already in the works is expected to contain the epidemic.
The oral polio vaccine is very effective and easy to administer. But because it uses live strains, but weakened virus, it causes associated paralytic polio vaccine in about 1 of every 750 000 people receiving, usually those whose immune system is weakened. There was no evidence that this form of the disease induced by the vaccine is contagious.
Now an epidemic on the island of Hispaniola demonstrates that the vaccine can mutate to a virulent form and spread. Three children in a rural area of the Dominican Republic and another child in a remote area of Haiti came down with paralytic poliomyelitis in July and August. None of the children had been vaccinated against the disease. Laboratory analysis, first by a local laboratory and then by the US Centers for Disease Control and Prevention in Atlanta, found that the children had been infected with a vaccine derived virus that had become virulent. The Pan American Health Organization (PAHO), which announced the results of the December 1, convened a group of scientists to study the data and recommend action.
The World Health Organization, PAHO is a division strives to eradicate polio worldwide by 05. That incident will delay the schedule remains to be seen, said Donald Henderson, an epidemiologist at Johns Hopkins University in Baltimore, Maryland, who led wHO's global eradication of smallpox successful. "We really want to focus on that and check in detail," says Henderson. "This comes as a big surprise for everyone."
Related Sites
The eradication program of the WHO polio
news of the release of PAHO about the epidemic
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