The association between live attenuated polio vaccine and cases of paralytic poliomyelitis dates back to the time of administration of the first live attenuated polio vaccine tried by Kolmer in the 1930s (Kolmer, 1936). Leake (1935) described nine cases of poliomyelitis that occurred following vaccination with the Kolmer vaccine and that seemed to be caused by the vaccine. The concept that live attenuated polio vaccine causes a small number of poliomyelitis cases thus has a history of at least six decades.
Shortly after licensing of Sabin's OPV, the United States Communicable Diseases Center (CDC; later named the Center for Disease Control, the Centers for Disease Control, and, more recently, the Centers for Disease Control and Prevention) reported its monitoring of vaccine-associated cases of paralytic polio. Henderson et al. (1964) summarized data for the United States collected by the CDC in 1962, 1963, and 1964. They evaluated 123 cases of paralytic polio that had occurred within 30 days of OPV administration and decided that 57 cases were compatible with vaccine-induced disease. Fifteen of the cases occurred after receiving the type 1 vaccine, with an estimated incidence of 0.17 case per 1 million doses. Thirty-six cases occurred following vaccination with the type 3 vaccine, with an incidence of 0.40 case per 1 million doses. Two cases occurred following vaccination with the type 2 vaccine, and four cases occurred following vaccination with the trivalent vaccine. The authors also described three cases of poliomyelitis that occurred in contacts of a recipient of the type 3 vaccine, but it is not clear whether the contact cases were included in the overall counts of vaccine-associated cases. Following publication of the paper by Henderson et al. (1964), case reports documenting vaccine-associated paralytic polio in recipients and contacts of recipients continued to appear. Table 7-1 summarizes the early case reports that described vaccine-associated poliomyelitis. By 1966, Chang et al. described a case of poliomyelitis in a 7-year-old recipient who was then found to have hypogammaglobulinemia. In 1966, Morse et al. documented a case of poliomyelitis in an unimmunized mother of a vaccinated infant. This was similar to the case of polio in an unimmunized father of a recently vaccinated infant reported by Swanson et al. (1967). Two reports provided evidence that contacts other than the parents or household members were also at risk of contracting polio. Balduzzi and Glasgow (1967) and Stolley et al. (1968) described unimmunized children who developed poliomyelitis after contact with recently vaccinated playmates or classmates.