Comparison of injected and oral polio vaccine for booster immunization during the 1979 polio outbreak in Lancaster County, Pennsylvania.

During a 1979 outbreak of poliomyelitis in Lancaster County, Pennsylvania, we investigated the necessity for and the response to booster vaccination of hospital personnel. The immune response of hospital employees who received booster injections of Salk vaccine (n = 38) was compared with that of residents in the surrounding community who received Sabin trivalent OPV boosters (n = 43). Serum neutralizing antibody titers to the three polio serotypes were measured before and after booster immunization. Results indicated that 38% of the subjects in both groups had low initial antibody titers. Salk vaccine was in all circumstances as effective or better than Sabin vaccine in increasing neutralizing IgG antibody titers.