Immune Responses in Human Volunteers Upon Oral Administration of a Rodent-Adapted Strain of Poliomyelitis Virus1

Twenty human volunteers were fed living poliomyelitis virus adapted to cotton rats, and characterized by very low pathogenicity for intracerebrally inoculated rhesus monkeys. Following oral administration of the virus, most of the volunteers manifested a carrier state demonstrated by excretion of virus in their stools, and all of the nonimmune volunteers promptly developed antibodies in their blood. In not a single instance were there any signs of illness noted. These findings are discussed in relation to the epidemiology of poliomyelitis.