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

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Malaria Infections Mosquito-Borne Diseases Parasitic Diseases Protozoan Infections Vector Borne Diseases

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Malaria Research and Training Center

Bamako, Mali

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Primary outcomes

Measurement of infection/infectivity incidences

Time frame: 1 year

Secondary outcomes

Measurement of infection intensity for a given mosquito that was fed on a given subject

Time frame: 1 year

Sponsors and collaborators

Lead sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Nih

Registry information

Official study title

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

Important dates

Study start: 2014
Primary completion: 2014
Study completion: 2014
First posted: Aug 1, 2014
Registry last updated: Dec 17, 2019

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed