This will be a multicenter, randomized, controlled, open-label, parallel-group Phase III study in healthy infants aged 6 to 8 weeks who have never been vaccinated against poliomyelitis. Approximately 900 infants will be included in the study and randomized with a 1:1:1 ratio to the following treatment groups:~Group A: approximately 300 subjects to receive 2 doses of nOPV2 administered 1 week apart, at Day 0 and Day 7;~Group B: approximately 300 subjects to receive 2 doses of nOPV2 administered 2 weeks apart, at Day 0 and Day 14;~Group C (control group): approximately 300 subjects to receive 2 doses of nOPV2 administered 4 weeks apart, at Day 0 and Day 28. A total of 4 on-site visits are planned. Approximately 7 days after each administration of study vaccine, a phone call or on-site visit will be performed to monitor subjects' safety and review with the subject's parent(s)/guardian(s) any solicited AEs reported in the electronic diary card. All subjects will have a safety follow-up phone call 6 months after the last dose of study vaccine.
Study to determine immunogenicity and safety following administration of 2 doses of novel oral poliovirus vaccine type 2 (nOPV2) given at different intervals of 1 week or 2 weeks or the standard 4-week interval in infants