IPV Clinical Trial - The Gambia

Inclusion Criteria: * Nine to ten months of age inclusive * Receipt of at least three doses of tOPV (excluding a dose given at birth) a minimum of four weeks prior to recruitment date * Informed consent for trial participation obtained from a parent/guardian (see section 19.1.2 for definition of guardian and section 19.1.3 for details regarding consent procedure) * Resident in the study area and with no plans to travel outside the study area during the period of subject participation * Willingness and capacity to comply with the study protocol as judged by a member of the clinical trial team Exclusion Criteria: * Use of any Investigational Medicinal Product(IMP) within the 28 days preceding enrolment * Planned administration of any vaccine outside those defined in the study protocol at anytime during trial participation (for procedure in the event of a national OPV campaign see section 12.5.1.1) * Previous receipt of a measles, rubella, yellow fever or IPV vaccine * Bacillus Calmette-Guérin(BCG) vaccination in the month prior to recruitment * Any suspected or confirmed congenital or acquired state of immune deficiency including but not limited to primary immunodeficiencies including thymus disorders, HIV/AIDS, hematological or lymphoid malignancies (blood tests will not be routinely undertaken with this regard as part of the study) * Any current immunosuppressive/immunomodulatory medication or treatment including, but not limited to corticosteroids, cyclosporin, azathiopri…