Improved Understanding of Ongoing Transmission of Leprosy in the Hyperendemic Comoros (ComLep)

Despite decades of a solid leprosy control program, including active case finding and follow-up on therapeutic outcome, the Comoros islands of Anjouan and Moheli continue to be hyperendemic for leprosy, with leprosy case notifications far exceeding those for tuberculosis, while the third island, Grande Comore, presents few cases. The high proportion (31% in 2015) of disease in children indicates that recent transmission is a major driver of the persistent endemicity, and that present control measures are not sufficient. The low proportion (2.6% average in last 10 years) of grade II disabilities in newly diagnosed cases indicates that case detection is early.

The main objective of the present proposal is to identify which persons would most benefit from prophylactic treatment. The secondary objective is to unravel human, bacterial and environmental risk factors for transmission of and progression to leprosy disease, with the ultimate goal to reduce the leprosy incidence.. The program has remaining expertise to re-establish laboratory confirmation of leprosy patients, allowing to optimize and validate molecular genotyping techniques to complement conventional epidemiological investigations in a 3-year prospective cohort of leprosy patients and their close contacts, aiming to identify transmission links. A third objective is to document diagnostic delays in more detail

As the leprosy control programme has initiated a pilot study on rifampicin prophylaxis in four villages on Anjouan in 2015, a prospective cohort study will permit measuring the leprosy incidence in close contacts as well as those in neighboring houses, who did or did not receive rifampicin prophylaxis.

The expected outcome of this project will be to identify risk factors for leprosy transmission. Specifically, we expect to identify those contacts at highest risk of developing leprosy disease, who would most benefit from rifampicin prophylaxis or other preventive measures.

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Key information

Conditions

Leprosy Actinomycetales Infections Bacterial Infections Bacterial Infections and Mycoses Gram-Positive Bacterial Infections Infections Mycobacterium Infections Mycobacterium Infections, Nontuberculous

Sex eligibility

All sexes

Study type

Observational

Primary location

Damien Foundation

Moutsamoudou, Anjouan, Comoros

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

in the prospective cohort study: All newly diagnosed leprosy patients (any age) on the island of Anjouan who provide written informed consent.
In the in-depth interviews: Patients who are part of a cluster and provide written informed consent. Additional written informed consent will be asked for questions in which the identity of other member(s) of a cluster needs to be revealed.

Exclusion criteria

in the prospective cohort study: None.
In the in-depth interviews: Patients belonging to clusters not extending beyond the same first or second circle

Treatment and study plan

Primary outcomes

Leprosy incidence among contacts of an index patient

Time frame: The incidence rate ratio will be recorded during the 3-year recruitment period op the study.

Incidence rate ratios among the contacts by proximity to the index patients will be calculated. Classification of contacts in proximity groups is a dynamic process. Persons belonging to the same household, surrounding households, entire village, or entire island may shift to closer proximity groups when leprosy patients are diagnosed in their environment. Since date of diagnosis, and any recent migration, will be recorded for each patient, we will be able to reallocate contacts to other circles and attribute to each contact a period of exposure within each circle.

Secondary outcomes

Recent transmission cluster

Time frame: All the samples over the three years should be analysed the able to fully explore the transmission links. Therefore, this outcome will be assessed through study completion, which will probably take1 year.

Transmission links will be defined as identical genotypes based on their "variable number of tandem repeat(VNTR)"- profile. The definition of clustering will be based on comparison of the copy number of the VNTRs using two different stringencies: either considering those that presented identical copy number for all 17 alleles, or considering those that had identical copy number excluding the most variable loci.
Patient and health system delay.

Time frame: This outcome can be calculated at the end of the recruitment phase of the study.Therefore, this outcome will be assessed through study completion, which will probably take1 year.

Mean patient and health systems delay with 95% confidence interval will be calculated. The questionnaire will comprise questions on the duration of the symptoms and the health seeking behavior of the patient.

Sponsors and collaborators

Lead sponsor

Institute of Tropical Medicine, Belgium

Other

Collaborators

Damien Foundation
Instituto Oswaldo Cruz
Programme National de lutte contre la Lèpre et la Tuberculose, Comores
R2STOP

Registry information

Official study title

Improved Understanding of Ongoing Transmission of Leprosy in the Comoros, a Region Hyperendemic for the Disease.

Acronym: ComLep

Important dates

Study start: 2017
Primary completion: 2020
Study completion: 2020
First posted: May 16, 2018
Registry last updated: May 11, 2021

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

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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.

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