Trivalent Oral Poliovirus Vaccine: A Comparison of Two Infant Immunization Schedules

The Public Health Service Advisory Committee on Immunization Practices (ACIP) and the Committee on Infectious Diseases of the American Academy of Pediatrics have not reached complete agreement in their currently recommended schedules for primary infant immunization with trivalent oral poliovirus vaccine (OPV). To determine which if either of these is the more efficacious, 200 infants were immunized with trivalent OPV. Approximately 50% of these infants completed the 3 dose primary series recommended by the ACIP; remaining infants completed the 4 dose series recommended by the Academy. Microneutralization titers to all three poliovirus types were determined at appropriate time intervals. At the completion of the study, a satisfactory percentage of individuals in both groups exhibited microneutralization titers of 1:10 or greater to all three poliovirus types. During the course of study, minor differences were noted between the two groups in the percentage of individuals with titers against poliovirus types 1 and 3.