Infant Infected With Polio

Health officials are investigating the case of an infant from central Minnesota who was infected with the virus that causes polio, the Minnesota Department of Health said. The infant is hospitalized but does not have symptoms of the paralytic illnesses that sometimes result from a polio infection, the department said. The child had previously been diagnosed with immune system problems. "It is important to note that there is no risk to the general public," Health Commissioner Dianne Mandernach said in a statement. But the department said this is the first case of polio infection reported in the United States since 2000, when the country stopped using the live-virus oral polio vaccine. The last case of naturally occurring polio in the United States was reported in 1979, and naturally occurring polio is considered eradicated in the Western Hemisphere. The last case of polio reported in Minnesota had been in 1992, and it was a vaccine-related case, according to the department's Web site. All vaccinations in the United States are now done with an injected, killed-virus vaccine. Before use of the live virus vaccine was halted, it caused an average of about eight cases of paralytic polio a year in the United States, the department said. The virus strain found in the Minnesota infant appears to be a variant of the oral vaccine strain, which is still used in some countries, the department said. State and federal health officials were trying to determine how the child became infected, but the virus can be transmitted by direct contact with the stool or oral secretions of an infected person, the department said. "Only unvaccinated people who have had direct contact with the infant are at risk, and we are following up directly with them to make sure their immunizations are up to date," said Kris Ehresmann, who heads the department's immunization section. "If you don't hear from a public health or health care official, you're not at risk." Citing state and federal data practice laws, the department said it could not release further information on the infant. The community and hospital involved were not disclosed. Ehresmann said the unusual case is a reminder for people to check with their health care providers to make sure their immunizations are up to date, and that their children are also protected. About 93 percent of Minnesota residents have had the full primary series of three polio shots, which was usually given during infancy.