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
500
Vaccination
International Centre for Diarrhoeal Diseases Research
Dhaka, Bangladesh
Poliovirus type-2 viral shedding
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) and IgA response to poliovirus type-2.
To assess and compare the pharyngeal NAbs activity, and poliovirus type-2-specific concentrations of pharyngeal mucosal immunoglobulin A (IgA) on D0, D14 and D28 in both groups.
Time frame: 1 month
Seroconversion rate of poliovirus type-2 neutralizing antibodies (NAbs)
To assess the cummulative seroconversion (SC) rate of poliovirus type-2 NAbs on D28 and D56 following administration of a challenge dose of nOPV2 in both groups.Seroconversion is defined as seropositive (titer ≥1:8) in those initially seronegative, or among those initially seropositive, as a minimum 4-fold higher titer (and seropositivity) than that which is expected due to maternal antibodies.
Time frame: 2 months
Incidence of 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
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