VIII. Immunological Effectiveness of the Two Dose Schedule †

The immunological effectiveness of the Middletown oral poliovirus vaccination program was determined by testing preand post-vaccinal neutralizing antibody levels in blood specimens from a selected group of children, representing about five per cent of the school children and 10 per cent of the preschool vaccinees. The present paper is concerned with the results of these tests in terms of the antibody status of the study group before they received oral vaccine, the conversion rates in antibody-negative children, and antibody rises in those with low levels before oral vaccination.