Assessing Immunogenicity of Intramuscular Sabin Inactivated Poliovirus Vaccine and Non-inferiority of Intradermal Fractional Inactivated Poliovirus Vaccine

Inclusion Criteria: * Healthy infants 6 weeks of age (range: 42-48 days). * Parents that consent for participation in the full length of the study (i.e., 34 weeks). * Parents that are able to understand and comply with planned study procedures. Exclusion Criteria: * A diagnosis or suspicion of immunodeficiency disorder either in the infant or in an immediate family member. * A diagnosis or suspicion of bleeding disorder that would contraindicate parenteral administration of sIPV or collection of blood by venepuncture. * Acute diarrhoea, infection or illness at the time of enrollment (6 weeks of age) that would require infant's admission to a hospital. * Acute vomiting and intolerance to liquids within 24 hours before the enrollment visit (6 weeks of age). * Evidence of a chronic medical condition identified by a study medical officer during physical exam. * Receipt of any polio vaccine (OPV or IPV) before enrollment based upon documentation or parental recall. * Known allergy/sensitivity or reaction to polio vaccine, or its contents. * Infants from multiple births. Infants from multiple births will be excluded because the infant(s) who is/are not enrolled would likely receive OPV through routine immunization and transmit vaccine poliovirus to the enrolled infant. * Infants from premature births (\<37 weeks of gestation).