Sabin 2 will be withdrawn from routine use globally from April 2016 as per the SAGE recommendations at the time of writing this protocol. After this cessation of OPV2, stockpiles of mOPV2 will be maintained for potential use if necessary in response to a future outbreak. However, there will be a risk of cVDPV2 from Sabin 2 in settings of low population immunity. Research is ongoing to develop vaccines that are genetically more stable than the currently available Sabin 2-containing OPVs. To generate data on immunogenicity, safety, and genetic stability on the Sabin 2 vaccine (mOPV2) and as a future comparator for new polio vaccine research after the global switch from tOPV to bOPV, this study with mOPV2 is performed to evaluate safety, immunogenicity (humoral and intestinal) and genetic stability endpoints of mOPV2 in children aged 1 to 5 years and in infants approximately 18 weeks of aged vaccinated with bOPV-/IPV for better understanding of the stockpile use of this vaccine, and for comparison with any potential new polio vaccine with a type 2 component in the future.
1. PRIMARY OBJECTIVE The primary objectives of the study are to assess the safety (serious adverse events \[SAEs\] and severe adverse events \[AEs\] grade 3 according to CTCAE 4.03 and immunogenicity (seroprotection rate) of a single dose of SABIN mOPV2 in healthy children aged 1 to 5 years old, and in infants at approximately 18 weeks of age after having been vaccinated with 3 doses of bOPV and 1 dose of IPV . 2. SECONDARY OBJECTIVES Secondary objectives are to assess: * The safety (mild and moderate solicited and unsolicited AEs, Important Medical Events \[IMEs\], and laboratory deviation assessments) of one or two doses of SABIN mOPV2 in healthy children aged 1 to 5 years, and of 2 doses of SABIN mOPV2 in infants at approximately 18 and 22 weeks of age after having been vaccinated with 3 doses of bOPV and 1 dose of IPV. * The immunogenicity (seroconversion rate, median and geometric mean antibody titers) of one or two doses of SABIN mOPV2 in healthy children aged 1 to 5 years old, and of two doses of SABIN mOPV2 in infants at approximately 18 22 weeks of age after having been vaccinated with 3 doses of bOPV and 1 dose of IPV. 3. EXPLORATORY OBJECTIVES Exploratory objectives are: * To investigate viral shedding following the SABIN mOPV2 administration. * Exploratory objectives may also include assessment of the genetic sequence heterogeneity and potential for neurovirulence (as measured in animal model(s)) of shed virus. * To investigate viral shedding and neurovirulence of shed virus; * To evaluate genetic reversion at position nt481 (primarily) and other secondary sites (e.g., nt2908). * To investigate the priming responses of bOPV for mOPV2. (group 2 only) and the duration of induction of anti-polio type 2 neutralizing antibodies .
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
164
SABIN monovalent OPV2 is a licensed, monovalent, live attenuated poliomyelitis virus vaccine of the Sabin strain Type 2 (P 712, Ch, 2ab), propagated in MRC5 human diploid cells. Each two-drop dose (0.1 mL) contains not less than 105.0 CCID50 of Type 2
Number of Subjects Experiencing SAEs, Severe AEs (Grade 3), and/or IMEs
Number of subjects experiencing SAEs, severe AEs (grade 3), and IMEs considered consistent with a causal association to study vaccine throughout the study period in all groups.
Time frame: 6 months
Seroprotection Rate of Type 2 Polio Neutralizing Antibodies.
Measured at Day 28 following a single dose of Sabin mOPV2 in both infant groups (Groups 2+3). Seroprotection is defined as type 2-specific antibody titers ≥1:8 and seroprotection rate as the percentage of seroprotected subjects per group.
Time frame: 28 days
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