Polio is a highly infectious disease caused by a virus. It invades the nervous system, and can cause total paralysis in a matter of hours. The virus enters the body through the mouth and multiplies in the intestine. Initial symptoms are fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs. One in 200 infections leads to irreversible paralysis (usually in the legs). Among those paralysed, 5% to 10% die when their breathing muscles become immobilized. There is no cure for polio, it can only be prevented. Polio vaccine, given multiple times, can protect a child for life.

Compare in newborns the immunogenicity and safety of the vaccine OPV produced by Birmex compared with the vaccine OPV produced by Sanofi Pasteur, both produced in Vero cells.

This is a randomized clinical trial, which includes 320 newborns of both sexes and residents of the state of México, 160 newborns receive the vaccine OPV Birmex and 160 newborns receive the vaccine OPV Sanofi Pasteur

Inclusion Criteria:

• Newborns babies
• Weight ≥ 2.5 kg
• Have not received any doses of Polio Vaccine
• Whose parents or guardians reside in the work area
• Whose parent or guardian accept to sign written informed consent (by the other, father or guardian).

Exclusion Criteria:

• Born of a high-risk pregnancy.
• Weight ≤ 2.5 kg
• Presence of fever, diarrhea, known immunosuppression, respiratory infections.
• Treatment with immunosuppressants.
• Having neurological diseases.
• Require or received surgery in oropharynx.