This is an open-label phase IV randomized clinical trial that will assess intestinal and humoral immunity among infants who receive a combination of monovalent oral poliovirus vaccine type 1 and fractional dose of inactivated poliovirus vaccine, monovalent oral poliovirus vaccine type 1 only, and bivalent oral poliovirus vaccine only.
The risk for circulating vaccine-derived poliovirus (cVDPV) will increase in the years immediately after the cessation of oral poliovirus vaccine (OPV) use in routine immunization programs. Judicious use of type-specific monovalent OPV (mOPV) will be necessary for outbreak response to prevent further paralytic infections and transmission; however, data on the intestinal and humoral immunity induced by mOPV1 are very limited. Furthermore, the additional benefit of fractional dose inactivated poliovirus vaccine (fIPV) on type 1 immunity when given with mOPV1 is unclear. Data on intestinal and humoral immunity of mOPV type 1 (mOPV1) and combination use of mOPV1 and fractional dose of IPV (fIPV) are urgently needed and would be used to inform guidelines for type 1 outbreak response in a post-OPV world. In the immediate future, a strategy of shifting from bivalent OPV (bOPV) to mOPV1 as part of supplemental immunization activities in endemic countries is under consideration but data on intestinal and humoral immunity to support this change does not exist. This trial is designed to address both areas in which data are lacking. Healthy infants 5 weeks of age will be enrolled at two study clinics in Dhaka, Bangladesh, and randomized to one of four study arms: mOPV1 + fIPV at 6 weeks, mOPV1 + fIPV at 14 weeks, mOPV1 only, and bOPV only. Infants will be followed-up until 18 weeks of age by clinic and household visits. Blood and stool specimens will be collected to test for vaccine response (humoral immunity) and vaccine virus shedding (intestinal immunity).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
1,256
Monovalent oral poliovirus vaccine type 1 is a type-specific, live, attenuated oral poliovirus vaccine that protects against poliovirus type 1.
Bivalent oral poliovirus vaccine is a live, attenuated oral poliovirus vaccine that protects against poliovirus types 1 and 3.
Fractional dose of inactivated poliovirus vaccine that protects against types 1, 2, and 3 (all polio serotypes). Given as a 0.1 milliliter (mL) dose (fractional) by intradermal injection in lieu of the full 0.5mL dose that is given intramuscularly.
icddr,b study clinics (Mirpur and CTU Dhaka)
Dhaka, Bangladesh
Vaccine response
Dichotomous (yes/no) variable defined as participants who are either seronegative (\<1:8 titers) at baseline who become seropositive (≥1:8) after vaccination (seroconversion) or participants who demonstrate a four-fold rise in titers after vaccination between two specimens, e.g. a change from 1:8 to 1:32, after adjusting for expected decay in maternal antibodies. Antibody titers at 6 weeks of age will be the starting point for the expected decline in maternal antibodies, assuming at half-life of 28 days.
Time frame: Measured four weeks after administration of study vaccine(s). Vaccine response will be measured at 10 weeks, 14 weeks, and 18 weeks of age after 1, 2, and 3 doses of OPV, respectively.
Vaccine virus particles
Presence or absence of vaccine virus particles in stool specimens.
Time frame: Measured 7 and 14 days after administration of the study vaccine. For Arms B, C, and D, this will be after administration of the first mOPV1 or bOPV dose. For Arms A, B, and C, this will be after the mOPV1 challenge dose at 14 weeks of age.
Reciprocal antibody titers
Variable of the observed reciprocal antibody titer results.
Time frame: Measured four weeks after administration of study vaccine(s). Vaccine response will be measured at 10 weeks, 14 weeks, and 18 weeks of age after 1, 2, and 3 doses of OPV, respectively.
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