It is expected that nOPV2 would replace mOPV2 for responding to type 2 outbreaks. Outbreak response for cVDPV2 also offers the opportunity to close immunity gaps to polioviruses types 1 and 3. Furthermore, GPEI might have to respond to two poliovirus outbreaks in the same geography. For either scenario, it would be important to get data on the immunogenicity of co-administered nOPV2 and bOPV, compared to either vaccine given alone.~This clinical trial assesses and compares the immunogenicity of nOPV2 given with or without bOPV. Healthy infants 6 weeks of age will be enrolled in Dhaka, Bangladesh, and randomized to one of three study arms â  Arm A: nOPV2 only, Arm B: nOPV2 and bOPV, or Arm C: bOPV only. Infants will be followed-up until 18 weeks of age through clinic and household visits. Blood specimens will be collected to test for immunological response. Stool specimens will be collected from infant vaccine recipients and one sibling household contact each to assess viral recombinants and nOPV2 household transmission.
This is an open-label randomized clinical trial that will compare immune responses among infants who receive either novel monovalent oral poliovirus vaccine type 2 (nOPV2) alone, bivalent oral poliovirus vaccine (bOPV) alone, or co-administered nOPV2 and bOPV.