The purpose of this study is to generate data to support the registration extension of IMOVAX Polio to be used in a sequential vaccination.

Primary objective:

• To demonstrate the non-inferiority of Inactivated Poliomyelitis Vaccine (IPV)-(Oral Poliomyelitis Vaccine) (OPV)-OPV (Sequential 1) and IPV-IPV-OPV (sequential 2) poliovirus vaccine administrations versus OPV-OPV-OPV (Reference) in terms of seroprotection rate 28 to 42 days after the third dose of the primary vaccination series.

Secondary objectives:

• To evaluate the safety profile of the investigational vaccines after each administration in each group.
• To describe the humoral immune response to poliovirus serotypes (types 1, 2 and 3) before the first dose and 28 to 42 days after the third primary series dose of vaccine in each group.
• To describe the persistence of antibodies against poliovirus serotypes (types 1, 2 and 3) after the third primary series dose administration, at 18 months of age in each group.

Study participants will be randomized to receive either 3 doses of a commercially available Oral Poliovirus Vaccine (OPV), or 1 dose of Sanofi Pasteur's injectable Inactivated Poliovirus Vaccine IMOVAX Polio (IPV) followed by 2 doses of OPV, or 2 doses of IPV followed by 1 dose of OPV.

These vaccines will be administered at 2, 3 and 4 months of age as primary vaccination for the prevention of poliomyelitis. Participants will be followed up through their 18th- to 19th-month birthday.

Inclusion Criteria:

• Aged ≥2 months and less than 3 months on the day of first study vaccine administration
• Born at full term of pregnancy (≥37 weeks) and with a birth weight ≥2.5 kg
• Informed consent form has been signed and dated by the parent or other legally acceptable representative
• Subject and parent/legally acceptable representative are able to attend all scheduled visits and to comply with all trial procedures.

Exclusion Criteria:

• Participation in the 4 weeks preceding the first trial vaccination or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure
• Receipt or planned receipt of any vaccine in the 4 weeks preceding or following any trial vaccination (except Diphtheria, Tetanus, acellular Pertussis vaccine [DTaP], Haemophilus Influenzae Type b [Hib] vaccine, bacille Calmette-Guerin vaccine [BCG] and Hepatitis B given at least 7 days before and after study vaccination)Previous vaccination against poliomyelitis with either the trial vaccine or another vaccine
• Receipt of immune globulins, blood or blood-derived products since birth
• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy since birth; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks since birth)
• Congenital or acquired immunodeficiency in close contacts to the subjects
• History of poliomyelitis infection (confirmed either clinically, serologically or microbiologically)
• At high risk for human immunodeficiency virus (HIV) infection during the trial
• Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the trial or to a vaccine containing any of the same substances
• Laboratory-confirmed or otherwise known thrombocytopenia, contraindicating intramuscular vaccination
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination
• Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
• Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion
• Moderate or severe acute illness/infection (according to investigator judgment) on the day of vaccination or febrile illness (axillary temperature ≥37.1°C). A prospective subject should not be included in the study until the condition has resolved or the febrile event has subsided
• Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study
• Any other contraindication as listed in the study vaccines' leaflets.