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

Sponsor
Zhejiang Provincial Center for Disease Control and Prevention (Other)
Overall Status
Active, not recruiting
CT.gov ID
NCT04817917
Collaborator
Liaoning Chengda Biotechnology CO., LTD (Industry)
712
3
5
22
237.3
10.8

Study Details

Study Description

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.

Condition or Disease Intervention/Treatment Phase
  • Biological: Japanese Encephalitis Vaccine (Vero Cell), Inactivated;
  • Other: No prospective interventions
Phase 4

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.

Study Design

Study Type:
Interventional
Actual Enrollment :
712 participants
Allocation:
Non-Randomized
Intervention Model:
Parallel Assignment
Masking:
None (Open Label)
Primary Purpose:
Prevention
Official Title:
Seroprevalence of Neutralizing Antibodies Against Japanese Encephalitis Virus Among 6 Years Old Children With 5 Different Immunization Strategies in Zhejiang Province, China: An Open-labeled, Ambidirectional Cohort Study
Actual Study Start Date :
Mar 1, 2021
Anticipated Primary Completion Date :
Aug 31, 2022
Anticipated Study Completion Date :
Dec 31, 2022

Arms and Interventions

Arm Intervention/Treatment
Experimental: 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.

Biological: 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.

Experimental: 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.

Biological: 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.

Experimental: 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.

Other: 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.

Experimental: 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.

Other: 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.

Experimental: 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.

Other: 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.

Outcome Measures

Primary Outcome Measures

  1. Proportions of seropositivity of neutralizing antibodies against JE at the age of 6 [At the age of 6. Test immediately after enrollment by a dose of blood sample.]

    Defined as any positive antibody (neutralizing antibody titers ≥1:10) response in children aged 6.

  2. Geometric Mean Titers (GMTs) or Median antibody titers for children aged 6 years [At the age of 6. Test immediately after enrollment by a dose of blood sample.]

    Neutralizing antibody titers by plaque-reduction neutralization tests (PRNT).

Secondary Outcome Measures

  1. Seroconversion rates of the booster dose of JEV-I for Group 1 and Group 2 [before and 28-35 days after the booster dose.]

    Defined as any positive antibody (neutralizing antibody titers ≥1:10) response in children who were seronegative prior to the booster dose, or at least a four-fold increase for children who had pre-existing positive antibodies.

  2. Proportion of seropositivity of neutralizing antibodies against JE after the booster dose for Group 1 and Group 2. [28-35 days after the booster dose.]

    Defined as any positive antibody (neutralizing antibody titers ≥1:10) response after the booster dose.

  3. Geometric Mean Titers (GMTs) or Median antibody titers after the booster dose for Group 1 and Group 2. [28-35 days after the booster dose.]

    Neutralizing antibody titers by PRNT.

  4. Safety of the booster dose for Group 1 and Group 2 [From inoculation to 30 days after the inoculation.]

    The occurrence of adverse events for the booster dose

Eligibility Criteria

Criteria

Ages Eligible for Study:
72 Months to 75 Months
Sexes Eligible for Study:
All
Accepts Healthy Volunteers:
Yes
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.

Contacts and Locations

Locations

Site City State Country Postal Code
1 Liandu center for disease control and prevention Lishui Zhejiang China 323000
2 Kecheng center for disease control and prevention Quzhou Zhejiang China 324000
3 Pingyang center for disease control and prevention Wenzhou Zhejiang China 325400

Sponsors and Collaborators

  • Zhejiang Provincial Center for Disease Control and Prevention
  • Liaoning Chengda Biotechnology CO., LTD

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.
Responsible Party:
Zhejiang Provincial Center for Disease Control and Prevention
ClinicalTrials.gov Identifier:
NCT04817917
Other Study ID Numbers:
  • ZJCDC20210317
First Posted:
Mar 26, 2021
Last Update Posted:
Jul 13, 2022
Last Verified:
Jul 1, 2022
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
No
Keywords provided by Zhejiang Provincial Center for Disease Control and Prevention
Additional relevant MeSH terms:

Study Results

No Results Posted as of Jul 13, 2022