This Phase III study has been designed to compare the SII Inactivated Salk Polio Vaccine (Adsorbed) with Sii licensed IPV by testing the vaccine in infants (three doses administered 4 weeks apart, starting at 6-8 weeks of age) in order to demonstrate the non-inferiority in the induction of specific poliovirus neutralizing antibody (PVNA) to poliovirus type 1, type 2 and type 3 by these vaccines. The study will also evaluate lot-to-lot consistency in the manufacture of SII Inactivated Salk Polio Vaccine (Adsorbed) by demonstrating equivalence in the induction of PVNA across three production lots.

The study is designed as a double-blind, randomized, active-controlled Phase III study with four groups of infants (n=268 per group) receiving either SII Inactivated Salk Polio Vaccine (Adsorbed) from the three lots or Sii licensed IPV.

Participants will be screened for eligibility with their parental consent and will be selected for the study according to inclusion and exclusion criteria. A total of 1072 participants will be enrolled.

Following vaccination, enrolled participants will remain in the clinic for at least 30 minutes for observation. During this time, they will be closely monitored for any immediate adverse events. Safety will be evaluated by active surveillance for solicited adverse events over the 4-day period after each vaccination in all participants. In addition, surveillance for unsolicited AEs and SAEs will be carried out over the period from first vaccination and 28 days after the third vaccination in all participants.

The immunogenicity will be assessed by measuring the PVNA to poliovirus type 1, type 2 and type 3 using a standardized microneutralization test in the sera samples of the participants.

Inclusion Criteria:

1. Healthy infants as established by medical history and clinical examination before entering the study
2. Age: 6-8 weeks at the time of enrolment
3. Parental ability and willingness to provide informed consent
4. Parent who intends to reside in the area with the infant during the study period

Exclusion Criteria:

1. Presence of fever on the day of enrolment [Temporary exclusion criteria].
2. Acute disease at the time of enrolment [Temporary exclusion criteria].
3. Prior receipt or intent to receive OPV/IPV/IPV containing vaccines during the study period.
4. OPV vaccination or known exposure to poliovirus (wild or vaccine derived) in household (living together) within 3-months prior to inclusion or planned during the study.
5. Presence of significant malnutrition (weight-for-height z-score < -3SD median)
6. Known or suspected impairment of immunological function based on medical history and physical examination.
7. Presence of any systemic disorder (cardiovascular, pulmonary, hepatic, renal, gastrointestinal, hematological, endocrine, immunological, dermatological, neurological, cancer, or autoimmune disease) as determined by medical history and / or physical examination which would compromise the participant's health or is likely to result in nonconformance to the protocol.
8. A known sensitivity or allergy to any components of the Investigational Product.
9. Receipt of immunoglobulin therapy and / or blood products since birth or planned administration during the study period
10. Planned concurrent participation in another clinical study at any point throughout the entire study period

The study is designed as a double-blind (observer blind) study. Observer-blind means that during study, the participants and the study personnel responsible for the evaluation of any study endpoints (e.g. safety and immunogenicity) will be unaware of the IP administered. The IP preparation and administration will be done by designated unblinded personnel who will not participate in any of the clinical study evaluations. Unblinded study personnel will prepare/reconstitute the IP out of view of the participant as well as the site staff. Considering the fact that the IP are likely to have distinct appearances, even when drawn into syringes, the syringes will be masked with an opaque wrapping before administration. After administration, the unblinded study personnel will complete accountability label on the carton and store the used products at designated area.