Complementary Study of the Duration of Post-vaccination Against Yellow Fever Immunity in Children

July 12, 2017 updated by: Olindo de Assis Martins Filho, Oswaldo Cruz Foundation
In a previous study by the researchers' group, the researchers' investigate the duration of yellow fever post-vaccination immunity in vaccinated children between 9 and 23 months of age. However, in this study, samples of children in the pre-vaccine period, also known as unvaccinated children samples (NV) have not been investigated. It is believed that to seek evidence about the immune status in the medium and long term after vaccination against yellow fever is necessary to investigate paired samples of children not vaccinated (NV), with re-evaluation 30-45 days after primary vaccination. The proposed study is to consolidate aspects of humoral (neutralizing antibodies) and cellular (phenotypic and functional parameters of T cells and memory B) by means of complementary longitudinal investigation children, 9-23 months old, unvaccinated (NV) and 30-45 days after primary vaccination.

Study Overview

Status

Unknown

Conditions

Detailed Description

A sample of 60 children aged 9 to 23 months paired in the pre-vaccine period (NV) and 30-45 post-primary vaccination days will be selected at health facilities in the metropolitan region of Belo Horizonte.

Children whose mothers consent to participate in research, have collected blood and elements of past medical history recorded. Analyses of humoral and cellular biomarkers will be used in a comparative study with other post-vaccination periods previously analyzed in children during the first phase in study funded by the Ministry of Health.

specific objectives:

  1. Estimate and compare the proportion of positivity and the geometric mean plasma titers of neutralizing antibodies against yellow fever;
  2. Assess lymphocyte frequency T and B memory induced in vitro by the vaccine antigen 17DD substrains, and...
  3. Quantify the lymphocytes T CD8 + producers of intracytoplasmic cytokines induced in vitro by the vaccine antigen 17DD substrains in unvaccinated children and primed aged between 9 and 23 months, categorized according to the vaccination time 30-45 days.

Study Type

Observational

Enrollment (Actual)

60

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Brazil
    • Minas Gerais
      • Belo Horizonte, Minas Gerais, Brazil, 30190002
        • Centro de Pesquisas Rene Rachou

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

9 months to 1 year (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

The study provides immunoassays paired before and after anti-yellow fever vaccination in children of both sexes, of any color, class or social group. This will be necessary 60 paired samples (pre-vaccine period and 30-45 days after primary vaccination) of children aged 9 to 23 months, living in areas where YF vaccine makes up the basic immunization calendar and will receive the vaccine in the routine of UBRs in the first two years of life. This study will be conducted with samples collected from children living in Ribeirão das Neves - Minas Gerais. It will be collected 7 mL of whole blood collected in Heparin Sodium. It will be allowed to make two attempts to collect only. These samples will be used for the realization of the humoral and cellular immunity study.

Description

Inclusion Criteria:

Will be eligible for the study:

  • children 9-23 months of age;
  • both sexes;
  • children who will be vaccinated against yellow fever, whose parents or guardians sign the consent form.

Exclusion Criteria:

  • children who received another vaccine within 30 days before or after the yellow fever vaccine;
  • children which have permanent or temporary immunosuppression, including those treated with corticosteroids at doses higher than 2 mg / kg, and those with disease autoimmune diseases, transient or permanent immunosuppression induced diseases (cancer, AIDS, etc.) or treatment (immunosuppressive drugs, radiotherapy, etc.). Corticosteroids (such as prednisone, dexamethasone) for less than two weeks, or by inhalation or topical use, do not indicate exclusion from the study, but must be registered in the questionnaire (Annex II);
  • children with hemoglobinopathies;
  • children with a history of blood transfusion or treatment with hyperimmune serum up to 90 days prior to blood collection.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Quantification of Humoral and cellular immunity after first yellow fever vaccination
Time Frame: Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Consolidating aspects of humoral (quantification of neutralizing antibodies - >2.log10IU/mL) and cellular (Percentege of phenotypic and functional parameters of T cells and B memory) through a complementary longitudinal investigation in children aged 9 to 23 month old unvaccinated and 30-45 days after first vaccination .
Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Quantification of titers of neutralizing antibodies in plasma samples
Time Frame: Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Quantify the titers of neutralizing antibodies against yellow fever immediately before and 30-45 days after primary vaccination against yellow fever in children 9-23 months of age without yellow fever vaccination history.
Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Evaluate the frequency (percentage) of T cells and B memory induced in vitro by the vaccine antigen 17DD
Time Frame: Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Evaluate the frequency (percentage) of T cells and B memory induced in vitro by the vaccine antigen 17DD immediately before and 30-45 days after primary vaccination against yellow fever in children 9-23 months old with no vaccination history against yellow fever.
Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Evaluate the frequency (percentage) of T and B cells expressing intracytoplasmic cytokines in vitro induced by the vaccine antigen 17DD
Time Frame: Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever
Evaluate the frequency (percentage) of T and B cells expressing intracytoplasmic cytokines (gama interferon; IL-5, alfa-TNF) CD8 + T lymphocytes, in vitro induced by the vaccine antigen 17DD immediately before and 30-45 days after primary vaccination against yellow fever, in children 9-23 months of age without yellow fever vaccination history.
Time 0 (immediately before) and Time 1 (30-45 days after) primary vaccination against yellow fever

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Oswaldo Cruz Foundation

Investigators

  • Principal Investigator: Olindo A Martins-Filho, PhD, Centro de Pesquisas Rene Rachou

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2015

Primary Completion (Actual)

April 1, 2017

Study Completion (Anticipated)

December 1, 2017

Study Registration Dates

First Submitted

September 1, 2015

First Submitted That Met QC Criteria

December 7, 2016

First Posted (Estimate)

December 13, 2016

Study Record Updates

Last Update Posted (Actual)

July 13, 2017

Last Update Submitted That Met QC Criteria

July 12, 2017

Last Verified

July 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CPqRR - M 02

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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