Seroprevalence of Neutralizing Antibodies Against Japanese Encephalitis Virus Among 6 Years Old Children With 5 Different Immunization Strategies in Zhejiang Province

NCT ID: NCT04817917

Last Updated: 2022-11-15

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: PHASE4
• Total Enrollment: 712 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-03-01
• Study Completion Date: 2023-06-30

Brief Summary

This study is to evaluate the seroprevalence of neutralizing antibodies against Japanese encephalitis (JE) virus in children aged 6 years who were previously administered with 5 different immunization strategies by JE attenuated live vaccine (JEV-L) or/and inactivated vaccine (JEV-I). The secondary objective is to evaluate the immunogenicity of the booster dose of JEV-I at 6 years old for those previously immunized with 3 doses of JEV-I or those sequential administered with 1 dose of JEV-L and another dose of JEV-I.

Detailed Description

Based on the retrospective registry in Zhejiang Provincial Immunization Information System, healthy children aged 6 years from 5 cohorts were included according to their previous immunization schedules on JE: 3 doses of JEV-I (Group 1), JEV-L+ JEV-I (Group 2), JEV-L+ JEV-I + JEV-I (Group 3), JEV-I + JEV-I+ JEV-L (Group 4), and 2 doses of JEV-L (Group 5). According to immunization programs in China, a booster dose of JEV-I is needed at the age of 6 for Group 1 and Group 2. A pre-vaccination blood sample (2.5ml) will be collected to evaluate the proportions of seropositivity before the booster dose of JEV-I. A second blood sample will be collected 28-35 days after the booster dose. Immunogenicity of the booster dose will be assessed by seroconversion rates, proportions of seropositivity and GMTs for these two groups. In addition, safety will be assessed with the occurrence of adverse events reported in these two groups. For the rest three groups who have completed the immunization schedules on JE, only one blood sample will be taken at the age of 6 to evaluate the proportions of seropositivity and GMTs after 4 years post the complete immunization schedules. Plague reduction neutralization test (PRNT) against both vaccine strains (SA-14-14-2 strain for JEV-L and Beijing P3 strain for JEV-I) will be used to test neutralizing antibody titers, so as to avoid potential bias in favor of either vaccine. PRNT50 titers (the reciprocal of the serum dilution that reduced the virus plaque count by 50% compared with the virus-only controls) ≥ 1:10 are deemed as positive.

Conditions

Japanese Encephalitis; Vaccine Preventable Disease; Vaccine Reaction

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

3JEV-I (Group 1)

Retrospective: 3 doses of JE vaccines. 2 doses of Inactivated JE Vaccine (JEV-I, 7-10 days apart) at 8 months of age and 1 dose of JEV-I at 2 years old.

Prospective: 1 booster dose of JEV-I at 6 years old.

Group Type: EXPERIMENTAL

Japanese Encephalitis Vaccine (Vero Cell), Inactivated;

Intervention Type: BIOLOGICAL

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. For participants from Group 1 and Group 2 who haven't completed the JE immunization schedules, a booster dose of JEV-I will be administered at 6 years old.

JEV-L+JEV-I (Group 2)

Retrospective: 2 doses of JE vaccines.

1 dose of JE attenuated live vaccine (JEV-L) at 8 months of age and 1 dose of JEV-I at 2 years old.

Prospective: 1 booster dose of JEV-I at 6 years old.

Group Type: EXPERIMENTAL

Japanese Encephalitis Vaccine (Vero Cell), Inactivated;

Intervention Type: BIOLOGICAL

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. For participants from Group 1 and Group 2 who haven't completed the JE immunization schedules, a booster dose of JEV-I will be administered at 6 years old.

JEV-L+2JEV-I (Group 3)

Retrospective: 3 doses of JE vaccines.

1 dose of JEV-L at 8 months of age and 2 dose (7-10 days apart) of JEV-I at 2 years old.

Group Type: EXPERIMENTAL

No prospective interventions

Intervention Type: OTHER

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. Participants from Group 3-5 have completed the JE immunization schedules with JEV-I or/and JEV-L. No prospective intervention will be given.

2JEV-I+JEV-L (Group 4)

Retrospective: 3 doses of JE vaccines. 2 doses of JEV-I (7-10 days apart) at 8 months of age and 1 dose of JEV-L at 2 years old.

Group Type: EXPERIMENTAL

No prospective interventions

Intervention Type: OTHER

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. Participants from Group 3-5 have completed the JE immunization schedules with JEV-I or/and JEV-L. No prospective intervention will be given.

2JEV-L (Group 5)

Retrospective: 2 doses of JE vaccines. 2 doses of JEV-L respectively administered at 8 months of age and 2 years old.

Group Type: EXPERIMENTAL

No prospective interventions

Intervention Type: OTHER

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. Participants from Group 3-5 have completed the JE immunization schedules with JEV-I or/and JEV-L. No prospective intervention will be given.

Interventions

Japanese Encephalitis Vaccine (Vero Cell), Inactivated;

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. For participants from Group 1 and Group 2 who haven't completed the JE immunization schedules, a booster dose of JEV-I will be administered at 6 years old.

Intervention Type: BIOLOGICAL

No prospective interventions

The investigators recruit 6 years old children who have been vaccinated by 2-3 doses of JE vaccines with different immunization strategies. Participants from Group 3-5 have completed the JE immunization schedules with JEV-I or/and JEV-L. No prospective intervention will be given.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Participants aged ≥ 72 months to < 75 months.
• Participants have completed routine immunization schedules in time.
• Participants are healthy native residents.
• Parents/guardians can understand the protocol requirements, provide informed consent, accept all scheduled visits, and comply with all trial procedures.

Exclusion Criteria

• History of neurological diseases or related symptoms.
• An acute illness with fever (temperature ≥ 37.1℃) or any acute onset of chronic diseases.
• Known impairment of immunologic function, or receipt of immunosuppressive therapy or immunoglobulin in the past 3 months.
• Known allergy to any constituent of the vaccine.
• Have been injected with other vaccines or any clinical trial drugs in the past 4 weeks.
• Any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the vaccine.

• Minimum Eligible Age: 72 Months
• Maximum Eligible Age: 75 Months
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Liaoning Chengda Biotechnology CO., LTD

INDUSTRY

Sponsor Role: collaborator

Zhejiang Provincial Center for Disease Control and Prevention

OTHER_GOV

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

Liandu center for disease control and prevention

Lishui, Zhejiang, China

Kecheng center for disease control and prevention

Quzhou, Zhejiang, China

Pingyang center for disease control and prevention

Wenzhou, Zhejiang, China

Countries

China

Other Identifiers

ZJCDC20210317

Identifier Type: -

Identifier Source: org_study_id