The study will compare the poliovirus type-2 pharyngeal mucosal excretion in the first week, and at 2 and 4 weeks following the administration of a challenge novel OPV2 (nOPV2) dose at 18 weeks of age in 2 parallel groups of infants
In the light of the switch from OPV to IPV and the continued presence of cVDPV2 in many countries, it is important to understand and quantify the impact of IPV on pharyngeal mucosal immunity, to inform whether and to what extent the mucosal and humoral immune response following IPV could reduce transmission and spread. This study will assess the effect of vaccination with IPV in parallel with poliovirus type-2 naïve infants (infants having received bOPV) on the pharyngeal and fecal shedding and the induction of immunity following type-2 poliovirus challenge. This understanding would provide critical information on the potential use of IPV in specific settings to interrupt transmission / reduce spread. The results from this study may potentially have important consequences on public health policy in countries which use IPV for infant priming, as they will help to show the extent to which a type-2 mucosal immunity gap remains following a primary series of IPV.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
501
Vaccination
International Centre for Diarrhoeal Diseases Research
Dhaka, Bangladesh
Number of Participants Shedding Detectable Levels of Poliovirus Type-2 by RT PCR.
To compare the presence of poliovirus type-2 in pharyngeal samples detected by reverse-transcription polymerase chain reaction (RT PCR) in the first week, and at D14 and D28 in both groups.
Time frame: 1 month
Pharyngeal Neutralizing Antibodies (NAbs) to Poliovirus Type-2.
To assess and compare the pharyngeal NAbs poliovirus type-2 activity on D0, D14 and D28 in both groups.
Time frame: 1 month
Seroprotection Rate to Poliovirus Type-2 on D0, D28 and D56 in Both Groups.
To assess the humoral immunogenicity to poliovirus type-2 at D0, 4 and 8 weeks following administration of a challenge dose of nOPV2 in both groups. Seroprotection is defined as neutralizing type-2 poliovirus antibody specific titers ≥1:8.
Time frame: 2 months
Number of Participants That Experienced Serious Adverse Events (SAEs) and Important Medical Events (IMEs)
To assess the number of subjects experiencing SAEs and IMEs following administration of IPV, bOPV and nOPV2 throughout the whole study period.
Time frame: 5 months
Pharyngeal Poliovirus Type-2-specific Immunoglobulin A (IgA) Concentrations
To asses and compare the pharyngeal mucosal immunoglobulin class-specific immune response to poliovirus type-2 at Day 0, 2 and 4 weeks following administration of a challenge dose of nOPV2 in both groups.This is measured in geometric mean concentrations (GMCs) in nasal samples on D0, D14 and D28 in both groups.
Time frame: 1 month
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