Outbreak in Caribbean blamed on low rate of immunization mutation of virus in vaccine.(Brief Article)

2002 APR 10 - (NewsRx.com & NewsRx.net) -- An outbreak of polio in Haiti and the Dominican Republic has been traced to a weakened virus in a vaccine that mutated and spread disease among poorly immunized children.

Even though Haiti and the Dominican Republic were declared polio-free in the 1980s, both countries reported cases of the paralyzing disease in the summer of 2000. The countries share the Caribbean island of Hispaniola.

Thirteen children were infected in the Dominican Republic and there were eight cases, including two deaths, in Haiti.

Teams from the U.S. Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization quickly responded, with disease detectives looking for the source of the disease.

In a study appearing March 15, 2002, in the electronic version of the journal Science, researchers report that they found the new cases of polio originated from the modified polio virus that was used in the oral vaccine, which is usually given on sugar cubes.

Olen M. Kew of the CDC, first author of the study, said the outbreak resulted from unprotected children coming in contact with children who had received the oral vaccine.

Patients given the vaccine develop a mild form of polio that results in an immunity to the disease. When this happens in a population that has not been inoculated, there is a chance that others may get the disease, Kew said.