Poliovirus infections in four unvaccinated children--Minnesota, August-October 2005.

On September 29, 2005, the Minnesota Department of Health (MDH) identified poliovirus type 1 in an unvaccinated, immunocompromised infant girl aged 7 months (the index patient) in an Amish community whose members predominantly were unvaccinated for polio. The patient has no paralysis; the source of the patient's infection is unknown. Subsequently, poliovirus infections in three other children within the index patient's community have been documented. This report summarizes the ongoing investigation, provides information regarding poliovirus exposure risks and prevention measures in the United States, and offers recommendations to state health departments and clinicians.