Enterics for Global Health (Efgh): Shigella Surveillance Study
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Date
2022-01-19
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Kamuzu University of Health Sciences
Abstract
Study type: The Enterics for Global Health (EFGH) Shigella surveillance study will employ crosssectional
and longitudinal study designs to establish updated incidence rates and document
consequences of Shigella diarrhea within 7 country sites in Africa, Asia, and Latin America.
Problem: Diarrhea remains a leading cause of death among young children, with most diarrhea
deaths occurring in low- and middle-income countries. Diarrhea caused by the bacterium
Shigella is responsible for an estimated 60,000 deaths each year and may cause particularly
severe illness among children. In low- and middle-income countries, nearly one third of children
experience at least one episode of Shigella-attributable diarrhea during their first 2 years of life.
In addition to it being a leading cause of diarrhea, this enteric bacterium is also associated with
linear growth faltering, a precursor to stunting. Stunting is a marker of vulnerability to childhood
infection, decreased vaccine efficacy and lifelong morbidity. Currently, there are several
promising vaccines to prevent Shigella diarrhea in development, but key information is still
needed to inform future vaccine studies.
Broad objective:
To determine the incidence of Shigella-attributed MAD in children 6 to 35 months of age.
Specific objectives:
1) To determine the incidence of Shigella MAD by serotype, severity definition, laboratory
method (culture vs. qPCR), age, and by season.
2) To describe the prevalence of resistance to commonly used antibiotics in Shigella isolates
in each EFGH country site.
3) To determine the risk of death, hospitalization, persistent diarrhea, diarrhea recurrence,
and linear growth faltering in the 3 months following an episode of Shigella MAD.
4) To compare various severity definitions in their ability to distinguish Shigella from non-
Shigella attributable diarrhea, and their ability to predict risk of death or hospitalization
in the subsequent 3 months following discharge from the health facility.
5) To qcuantify the cost incurred by families and health care systems due to Shigella
morbidity and mortality.
6) To identify optimal laboratory methods for Shigella culture by comparing the isolation
rate of Shigella between two transport media for rectal swabs (Cary-Blair and modified
Buffered Glycerol Saline [BGS])
7) To determine the serum immune responses to Shigella infection, utilizing acute and
convalescent blood samples.
Methodology: Over a two-year period, the EFGH study will enroll 9,800 children (1,400 per
country site) between 6-35 months of age with MAD. In Malawi, the population under
surveillance will comprise residents of Ndirande Township, with children recruited from
Ndirande District Health Centre. and the Queen Elizabeth Central Hospital, Blantyre. Population
enumeration and healthcare utilization studies will be undertaken to inform Shigella-attributed
MAD incidence estimates. A stool sample will be obtained from each child on enrolment and
examined for Shigella by culture and qPCR. Acute and convalescent dried blood spot samples
will be examined for Shigella antibody using ELISA. Children will be followed following discharge
for three months to allow assessment of clinical outcomes, growth, and costs attributed to
Shigella infection.
Expected Results and Dissemination: Eventual Phase 2b/3 Shigella vaccine trials will require a
consortium of potential vaccine trial sites in settings with a high incidence of Shigella-attributed
MAD, high participant retention, and the laboratory capacity to confirm Shigella infection.
Through this multi-country surveillance network, selected EFGH sites will be ready to quickly
implement rigorous and efficient vaccine trials and provide critical data to policy makers about
the relative importance of this vaccine-preventable disease, accelerating the time to vaccine
availability and uptake among children in high Shigella burden settings. The study findings will
be shared with the College of Medicine Research Ethics Committee (COMREC), the Ministry of
Health (MoH), published in peer reviewed journals and will be disseminated to the public
through the annual College of Medicine Research dissemination conference.
Description
Keywords
Incidences of diarrhea