Olen Kew is an expert in viruses for the Centers for Disease Control. Among his studies is the polio known as vaccine-associated-paralytic polio, or VAPP. He says the United States had about eight such cases a year before two thousand, when the oral polio vaccine was being used. About twenty percent of the cases were in children who had problems with their own natural defenses against disease.

BOB DOUGHTY: If there is any chance of a case of VAPP developing, why give Sabin oral polio vaccine? Experts say this vaccine works faster against the spread of type one polio. And it is not costly. Health care workers who direct its use need little training.

Olen Kew notes that many developing countries use the vaccine because children can receive it without injection. The Sabin oral polio vaccine also protects the intestines. That prevents the spread of the disease from person to person.

But the virus expert says, “There is always the risk that the weakened strains of the virus used in the vaccine will mutate into a form that can cause severe illness and even death.”

(MUSIC)

FAITH LAPIDUS: Jonas Salk developed the first major polio vaccine in the nineteen fifties. Albert Sabin then developed the Sabin oral polio vaccine in the nineteen sixties. Doctor Salk’s polio vaccine was injected. An improved version of the Salk vaccine is now used in the United States.

Poliovirus was first identified in nineteen eight, long before Doctors Salk and Sabin produced their vaccines. The earlier scientists, the discoverers, recognized the sickness. But they could not stop people from getting infected with it.