Although vaccination has almost eliminated poliomyelitis in western Europe, Canada, the United States, Australia, Japan, and New Zealand, the disease is still extant in developing countries. Approximately 250,000 cases occur each year. Transmission is fecal-oral. A recent outbreak in Israel was linked to waning immunity in adults who had received the inactivated vaccine in childhood. Outbreaks are occasionally reported from religious groups who abstain from vaccination.
Most persons are asymptomatic.
Involvement of the cranial nerves may cause bulbar paralysis. Preparing the international traveler The Centers for Disease Control and Prevention recommend that all travelers to developing countries be fully immunized against poliomyelitis. Two vaccine products are available. This is a live vaccine and is the primary vaccine used in children under the age of 18. The risk of acquiring paralytic polio from the vaccine is one in several million.