Assessing Human-to-Mosquito Transmission in Volunteers Participating in Malaria Vaccine Candidate Trials in Mali

December 14, 2019 updated by: National Institute of Allergy and Infectious Diseases (NIAID)

Assessing Human-to-Mosquito Transmission in Volunteers Participating in Malaria Vaccine Candidate Trials in Don(SqrRoot)(Copyright)gu(SqrRoot)(Copyright)Bougou Mali

Background:

- Malaria is a disease that affects many people in Mali and in Africa. It is caused by germs that are spread by mosquito bites. Researchers are creating vaccines that they hope will prevent malaria infection and/or the spread of it.

Objective:

- To test if the PfSPZ vaccine can stop malaria spread by mosquitoes.

Eligibility:

- People currently enrolled in the ongoing PfSPZ malaria vaccine trial. Participants must be willing to have uninfected mosquitoes bite them.

Design:

  • Participants will be able to take part in this study at every visit after receiving all scheduled vaccinations.
  • Participants will be asked whether they are willing to participate in the procedures. Female participants will have a pregnancy test.
  • Researchers will put about 60 mosquitoes in 2 or 3 cups (20 or 30 in each cup). They will hold each cup to the participant s leg or arm so the mosquitoes can bite. These mosquitoes do not carry germs and will take about 3 drops of blood total.
  • Participants will get a cream for any swelling or itching.
  • Participants will be checked the next day for any discomfort.
  • Participants may take part in this feeding test multiple times, if they are willing.
  • If participants have malaria parasites in their blood, they may be asked to take part in another study. For this, they will sleep alone in their hut the night after the feeding test. A study team will set up nets to collect mosquitoes that may have bitten the participant overnight.

Study Overview

Status

Completed

Conditions

Detailed Description

A vaccine which interrupts malaria transmission (VIMT) is a critical tool to achieve the ultimate goal of eradication of this disease. VIMTs work by inducing humoral responses in vaccinated individuals that inhibit the development of malaria parasites in the mosquito, and combined humoral and cellular responses that inhibit the establishment of infection in humans. Overall efficacy of these vaccines is evaluated by measuring reduction of infection and clinical cases among vaccinees and the parasite infectivity to mosquitoes, (human-to-mosquito transmissibility), before and after vaccination, and with or without vaccination. One of the candidate VIMTs, the PfSPZ Vaccine, is currently being tested in Mali for safety, tolerance, and immunogenicity.

The objective of this Feeding Assay Protocol is to explore the effect of the PfSPZ Vaccine, on interrupting human-to-mosquito transmission. Individuals from the the PfSPZ Vaccine trial in 2014 who also consent to be enrolled in this Feeding Assay Protocol will be eligible to participate in procedures including direct skin feeds (DSF) and experimental huts (EH). The human-to-mosquito transmission will be evaluated by examining the presence of malaria parasites in the midgut of mosquitoes fed on study participants. The human-to-mosquito transmission by DSF and EH assay methods will be analyzed for potential correlation.

Study Type

Observational

Enrollment (Actual)

87

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

  • Mali
      • Bamako, Mali
        • Malaria Research and Training Center

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

18 years to 35 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

  • INCLUSION CRITERIA:
  • Currently enrolled in the PfSPZ Vaccine trial.
  • Willingness to participate in the study as evidenced by signing the informed consent document, or by fingerprinting the consent document and obtaining the signature of a witness.

EXCLUSION CRITERIA:

  • Refusal to participate
  • Known history of abnormal reaction to mosquito bites
  • Any condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the DSF or EH procedures or would render the volunteer unable to comply with the Feeding Assay Protocol.
  • Pregnancy
  • Any condition that in the opinion of the investigator would withdraw the volunteer from vaccine trial.

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: Case-Only
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Measurement of infection/infectivity incidences
Time Frame: 1 year
1 year

Secondary Outcome Measures

Outcome Measure
Time Frame
Measurement of infection intensity for a given mosquito that was fed on a given subject
Time Frame: 1 year
1 year

Collaborators and Investigators

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

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

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

July 16, 2014

Primary Completion (Actual)

July 16, 2014

Study Completion (Actual)

July 16, 2014

Study Registration Dates

First Submitted

July 31, 2014

First Submitted That Met QC Criteria

July 31, 2014

First Posted (Estimate)

August 1, 2014

Study Record Updates

Last Update Posted (Actual)

December 17, 2019

Last Update Submitted That Met QC Criteria

December 14, 2019

Last Verified

June 29, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 999914159
  • 14-I-N159

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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