The mainstay of control of soil-transmitted helminths (STH) is school-based deworming but recent modelling has highlights that in all but low very transmission settings, the treatment of school-aged children is unlikely to interrupt transmission, and that new treatment strategies are required. This study seeks to answer the question: is it possible to interrupt the transmission of STH and if so, what is the most cost-effective treatment strategy and delivery system to achieve this goal? In this study, two paired community cluster randomised trials in different settings in Kenya will evaluate the impact and cost-effectiveness of annual school-based deworming, annual community-based deworming, and biannual community-based deworming. The interventions are (i) annual mass anthelmintic treatment delivered either to pre-school and school-aged children, as part of a national school-based deworming programme, or to the entire community delivered by community health workers. The primary outcome measure is the prevalence of hookworm infection (the most common STH species), assessed by periodic cross-sectional, age-stratified parasitological surveys. Secondary outcomes include intensity of hookworm, prevalence and intensity of Ascaris lumbricoides, treatment coverage, and among a randomly selected sub-sample of participants who will be followed longitudinally, worm burden and proportion of eggs unfertilised. A nested process evaluation, using semi-structured interviews, focus group discussions and a stakeholder analysis will investigate the community acceptability, feasibility given the local and regional health system structures and processes, and scale-up of the interventions.
The study will be conducted in two settings of Kenya that have contrasting epidemiological and programmatic characteristics, Kwale County on the south Kenyan coast and Bungoma County in western Kenya. Allocation to study group will be by cluster, using predefined units used in public health provision - termed Community Units (CUs), which comprise approximately 1,000 households or 5,000 people. CUs will be randomized to one of three groups, receiving either (i) annual school-based deworming; (ii) annual community-based deworming; (iii) biannual community-based deworming. In nine CUs, a longitudinal study will be conducted in order to better understand the transmission dynamics of STH.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
21,761
Single dose of albendazole (400 mg)
Kenya Medical Research Institute
Nairobi, Kenya
Prevalence of hookworm in community members
The prevalence of hookworm will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Parasite prevalence will be defined as the proportion of slides that are positive for hookworm eggs. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months. In a random subset of individuals, additional confirmatory diagnosis of infection will be based on real-time polymerase chain reaction (PCR).
Time frame: Endline survey conducted, approximately 24 months after starting the intervention
Prevalence of Ascaris lumbricoides in community members
The prevalence of Ascaris will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Parasite prevalence will be defined as the proportion of slides that are positive for hookworm eggs. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months. In a random subset of individuals, additional confirmatory diagnosis of infection will be based on real-time PCR.
Time frame: Endline survey conducted, approximately 24 months after starting the intervention
Intensity of infection for each STH species
The intensity of STH species will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Intensity of infection will be quantified as eggs per gram of faeces. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months.
Time frame: Endline survey conducted, approximately 24 months after starting the intervention
Treatment coverage
• Treatment coverage will be measured using both routine data, and data collected during scheduled STH stool surveys. Teachers and community health workers (CHWs) will be provided with treatment registers and asked to provide a full record of all individuals who have received treatment. To augment these data, population-based coverage surveys using multistage clustering sampling will be carried out among a random subsample of communities.
Time frame: Up to month following treatment
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