This phase II, randomized, controlled trial’s motive was to assess the safety and immunogenicity of various Sabin IPV preparations. On a 0-1-2 month schedule, 600 babies aged 60-90 days received one of five distinct vaccines: low- (group A), medium- (group B), or high-D antigen content (group C) of the Sabin IPV (experimental), control Sabin IPV (group D), or control Salk IPV (group E). To determine protection, participants were examined and followed up on within 30 days of each dosage. Serum samples have been collected for immunogenicity before the first dose and 30 days after the third dose. After 3 doses of seroconversion frequencies, type-1 in groups A–E was 99.1%, 100.1%, 99.1%, 99.0% and 93.4% respectively; type-2 seroconversion rates were 93.5%, 97.1%, 99.1% and 91.5% respectively; and type-3 seroconversion rates were 95.4%, 98.1%, 96.1% and 100.0%, respectively. 97.1%, 99.1% and 91.5% respectively. For category E only the sero-1 rate differed substantially.

Injection-site redness, swelling, and discomfort were all significantly higher for experimental vaccines. There were no SAEs found to be associated with vaccination, and the majority of adverse reactions were mild to moderate in severity. Finally, despite being more reactogenic than the control vaccines, the experimental Sabin IPVs with low-, medium-, and high-D antigen content all demonstrated good safety and immunogenicity profiles.