Cross-neutralization Capacity of Immune Serum From Different Dosage of Sabin Inactivated Poliovirus Vaccine Immunization

Study Overview
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Brief Summary
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This study is a supplementary study of an already finished randomised, double-blinded, and placebo controlled phase 2 clinical trial of an Sabin strain inactivated poliovirus vaccine (sIPV) manufactured by Sinovac Biotech Ltd., Beijing China. The purpose of this study is to evaluate the cross-neutralization capacity of the serum immuned by the investigational sIPV against 10 individual virus strains.

Detailed Description
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This study is a open-labelled study conducted based on an already finished phase 2 study of the investigational sIPV in 600 healthy infants aged 2-months old. The purpose of this study is to evaluate the cross-neutralization capacity of the serum immuned by the investigational sIPV against 10 individual virus strains. Paired pre-immune and post-immune serum from 250 participants of the phase 2 trial, with 50 in each group including the low-, medium- and high- dosage group, control wild poliovirus vaccine (wIPV) group and control sIPV group, was selected and sent to China Center for Disease Control and Prevention (CDC) for the cross-neutralization assay to determine the neutralizing antibody titer against 10 individual virus strains including Sabin strains (type 1, 2, and 3), Salk strains (Mahoney, MEF-1, and Saukett), cVDPV (type 1, 2, and 3) and Xinjiang wild strain of type 1(Xinjiang wIPV1). All the subjects in this study had been vaccinated at the schedule of month 0,1, and 2 in the phase 2 clinical trial.

Official Title
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Cross-neutralization Capacity of Immune Serum From Different Dosage of Sabin Inactivated Poliovirus Vaccine Immunization Against Multiple Individual Wild and Vaccine-derived Polioviruses, Supplementary Study of a Phase 2 Clinical Trial.

Conditions
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Poliomyelitis

Intervention / Treatment
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* Biological: Three doses of low-dosage investigational sIPV, vaccinated within one-month interval between doses
* Biological: Three doses of medium-dosage investigational sIPV, vaccinated within one-month interval between doses
* Biological: Three doses of high-dosage investigational sIPV, vaccinated within one-month interval between doses
* Biological: Three doses of control wIPV, vaccinated within one-month interval between doses
* Biological: Three doses of control sIPV, vaccinated within one-month interval between doses


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants of the already finished phase 2 clinical trial; Subjects who received the three-doses full schedule vaccination required in the phase 2 tril and can provide the backup paired pre-immune and post-immune serum collected in the phase trial; Provide written informed consent. Exclusion Criteria: None.

Ages Eligible for Study
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Minimum Age: 2 Months
Maximum Age: 2 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low-dosage experimental group<br>Three doses of low-dosage investigational sIPV, vaccinated within one-month interval between doses | Biological: Three doses of low-dosage investigational sIPV, vaccinated within one-month interval between doses<br>* Antigen content: 7.5, 22.5, and 22.5 D-antigen unite for type 1, 2, and 3 in 0.5 ml diluent per dose<br>|
| Experimental: Medium-dosage experimental group<br>Three doses of medium-dosage investigational sIPV, vaccinated within one-month interval between doses | Biological: Three doses of medium-dosage investigational sIPV, vaccinated within one-month interval between doses<br>* Antigen content: 15, 45, and 45 D-antigen unite for type 1, 2, and 3 in 0.5 ml diluent per dose<br>|
| Experimental: High-dosage experimental group<br>Three doses of high-dosage investigational sIPV, vaccinated within one-month interval between doses | Biological: Three doses of high-dosage investigational sIPV, vaccinated within one-month interval between doses<br>* Antigen content: 22.5, 67.5, and 67.5 D-antigen unite for type 1, 2, and 3 in 0.5 ml diluent per dose<br>|
| Active Comparator: Control wIPV group<br>Three doses of control wIPV, vaccinated within one-month interval between doses | Biological: Three doses of control wIPV, vaccinated within one-month interval between doses<br>* Antigen content: 40, 8, and 32 D-antigen unite for type 1, 2, and 3 in 0.5 ml diluent per dose<br>|
| Active Comparator: Control sIPV group<br>Three doses of control sIPV, vaccinated within one-month interval between doses | Biological: Three doses of control sIPV, vaccinated within one-month interval between doses<br>* Antigen content: 30, 32, and 45 D-antigen unite for type 1, 2, and 3 in 0.5 ml diluent per dose<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunity index of seroconversion rate | The seroconversion rates of neutralizing antibody against 10 individual virus strains (Sabin 1, Sabin2， Sabin 3, Mahoney 1, MEF-1, Saukett, cVDPV1, cVDPV2, cVDPV3, and Xinjiang wIPV1) | One month after three doses of vaccination | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunity index of geometric mean titer (GMT) | The GMT of neutralizing antibody against 10 individual virus strains (Sabin 1, Sabin2， Sabin 3, Mahoney 1, MEF-1, Saukett, cVDPV1, cVDPV2, cVDPV3, and Xinjiang wIPV1) | One month after three doses of vaccination | 
| Immunity index of geometric mean ratio (GMR) | The GMR of neutralizing antibody against 10 individual virus strains (Sabin 1, Sabin2， Sabin 3, Mahoney 1, MEF-1, Saukett, cVDPV1, cVDPV2, cVDPV3, and Xinjiang wIPV1) | One month after three doses of vaccination | 
| Immunity index of seropositivity rate | The seropositivity rate of neutralizing antibody against 10 individual virus strains (Sabin 1, Sabin2， Sabin 3, Mahoney 1, MEF-1, Saukett, cVDPV1, cVDPV2, cVDPV3, and Xinjiang wIPV1) | One month after three doses of vaccination |