Inactivated Influenza Vaccine Effectiveness in Tropical Africa

September 19, 2013 updated by: PATH

Assessment of the Effectiveness of Seasonal Trivalent Influenza Vaccine Among Children in Senegal

Influenza, a highly communicable acute respiratory disease, is one of the major infectious disease threats to the human population. In Africa, information on the occurrence of influenza and its disease burden is seriously lacking. Such data would be important in determining the contribution of influenza to the more than two million annual pneumonia deaths among children globally, mostly in the developing world, and the potential number of deaths that could be prevented by influenza vaccination.

A single dose of trivalent inactivated influenza vaccine (TIV) is 70 to 90 percent effective in preventing influenza in healthy older children and young and middle-aged adults, but is less efficacious in young children and the elderly. Young children who suffer substantial influenza morbidity and are unlikely to have pre-existing immunity should receive two doses of TIV to provide adequate immunity. Because family studies of influenza transmission conducted during the 1970's found children to be the main introducers of influenza into households, vaccination of children may decrease the chances of spreading influenza to contacts. Mass vaccination of schoolchildren has been correlated with reduced respiratory illness in unvaccinated persons suggesting that immunization of children on a larger scale can affect community epidemics.

In temperate industrialized countries with seasonal disease, influenza vaccine is given annually, prior to the influenza season, and generally targeted to individuals with the highest risk of severe disease. Influenza prevention strategies may need to differ in tropical developing countries due to a variety of reasons. Given the varying influenza circulation patterns, it is unknown which hemisphere vaccine formulation will provide year-round protection against the diverse strains that may exist in tropical countries. Persons residing in developing countries also may have nutritional deficiencies or underlying diseases and infections that affect vaccine immunogenicity. Consideration must be given to programmatic issues as well. Adolescent and adult preventive health services are poorly developed in many countries, and thus a strategy that targets children may be the most feasible option. In addition, vaccinating children may be the most cost-effective option, as it has the potential to provide direct benefit to those vaccinated, as well as indirect benefits to unvaccinated members of the population. Thus, an influenza vaccine effectiveness study in a tropical developing country population will help to elucidate burden of seasonal influenza and may inform optimal use of vaccine for either seasonal and pandemic situations.

Thus, this study in Senegal will to evaluate the direct effects of TIV in reducing the occurrence of laboratory-confirmed influenza among children who receive it as well as the potential indirect effects experienced by the population as a result of reducing transmission among children.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The trial will take place in the study area of the Niakhar demographic surveillance system in Senegal, a population representative of rural impoverished Africa. Villages will be randomized to TIV or a beneficial control vaccine-inactivated polio vaccine-and children 6 months to 10 years of age will be targeted for vaccination. Four hundred children will be further enrolled into an immunogenicity and safety substudy which will measure their immune response to vaccination and assess in detail reactions and adverse events to the vaccines in these populations. For evaluation of effectiveness, passive and active surveillance will be conducted to identify laboratory-confirmed influenza among enrolled children and in the population in which they live. Such surveillance will also allow a determination of the rates of influenza and a description of the clinical characteristics of the disease in an African population. With such epidemiologic data, national and global public health officials will have better data for developing future influenza control strategies for either seasonal or pandemic influenza.

Study Type

Interventional

Enrollment (Anticipated)

10000

Phase

  • Phase 4

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

  • Senegal
    • Fatick District
      • Niakhar, Fatick District, Senegal
        • Niakhar Demographic Surveillance System

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

6 months to 10 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • A male or female child at least 6 months of age and no older than 10 years of age (has not yet reached 11 years of age) at the enrollment visit.
  • A child whose parent or guardian's primary residence, at the time of study vaccinations, is a village compound selected to receive TIV or IPV.
  • Subject's parent or legal guardian is willing to provide written informed consent prior to the subject's first study vaccination.

Exclusion Criteria:

  • Hypersensitivity to the active substance or any component in either TIV (which includes egg protein) or IPV. (Please see information on composition of vaccines.)
  • Hypersensitivity after previous administration of any influenza or polio vaccine.
  • Acute severe febrile illness. (Administration of TIV or IPV should be postponed until after recovery. Minor illnesses, such as mild upper respiratory infection, with or without low grade fever, are not reason for postponing vaccination. Acute severe febrile illness is only a temporary exclusion.)
  • Any condition that, in the opinion of the investigator, would pose a health risk to the participant or interfere with the evaluation of the study objectives.

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

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: TIV
Children living in villages randomized to influenza vaccine
Biological: seasonal trivalent inactivated influenza vaccine
vaccine to be used according to marketed dosage and frequency
Other Names:
  • Vaxigrip
Experimental: IPV
Children living in villages randomized to polio vaccine
Biological: inactivated polio vaccine
vaccine to be used according to marketed dosage and frequency
Other Names:
  • Imovax Polio

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Total effectiveness of vaccine against laboratory-confirmed symptomatic influenza.
Time Frame: Two weeks post-vaccination through February 28 the following calendar year
Two weeks post-vaccination through February 28 the following calendar year

Secondary Outcome Measures

Outcome Measure
Time Frame
Indirect effectiveness against laboratory-confirmed symptomatic influenza
Time Frame: Two weeks post-vaccination through February 28 the following calendar year
Two weeks post-vaccination through February 28 the following calendar year
Overall effectiveness of vaccine against laboratory-confirmed symptomatic influenza
Time Frame: Two weeks post-vaccination through February 28 the following calendar year
Two weeks post-vaccination through February 28 the following calendar year
Direct effectiveness of vaccine against laboratory-confirmed symptomatic influenza
Time Frame: Two weeks post-vaccination through February 28 the following calendar year
Two weeks post-vaccination through February 28 the following calendar year

Collaborators and Investigators

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

Sponsor

PATH

Collaborators

Centers for Disease Control and Prevention
Institut Pasteur
Institut de Recherche pour le Developpement

Investigators

  • Study Director: John C Victor, PhD, MPH, PATH
  • Principal Investigator: Aldiouma Diallo, MD, IRD

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

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

May 1, 2009

Primary Completion (Actual)

December 1, 2012

Study Completion (Actual)

April 1, 2013

Study Registration Dates

First Submitted

May 4, 2009

First Submitted That Met QC Criteria

May 5, 2009

First Posted (Estimate)

May 6, 2009

Study Record Updates

Last Update Posted (Estimate)

September 23, 2013

Last Update Submitted That Met QC Criteria

September 19, 2013

Last Verified

September 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TIV-SEN-01

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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