Child, Diarrhea, Shigella
Conditions
Keywords
Epidemiology, Shigella, Diarrhea, Children, Enterics, Vaccine
Brief summary
Diarrhea remains a leading cause of death among young children, with the majority of diarrhea deaths occurring in low- and middle-income countries. Childhood diarrhea caused by a type of bacteria called Shigella is responsible for an estimated 60,000 deaths each year and may cause particularly severe illness among children. Currently, there are several promising vaccines to prevent Shigella diarrhea in development, but key information is still needed to inform future vaccine studies. The purpose of this study, titled Enterics for Global Health (or the EFGH), is to determine the number and rate of new cases of Shigella diarrhea among children 6 to 35 months of age presenting to health facilities with diarrhea or dysentery. Over a two-year period, the EFGH study will enroll 1,400 children from each of the seven countries: Peru, Pakistan, Bangladesh, Mali, Malawi, Kenya, and The Gambia (9,800 children total).
Detailed description
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, several promising Shigella vaccines are in development. 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 medically-attended diarrhea, high participant retention, and the laboratory capacity to confirm Shigella infection. The Enterics for Global Health (EFGH) Shigella burden study will employ cross-sectional 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. Over a two-year period, the EFGH study will enroll 9,800 children (1,400 per country site) between 6-35 months with medically-attended diarrhea. 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. Primary Aims 1\. Determine the incidence of Shigella-attributed medically-attended diarrhea in children 6 to 35 months of age in each of the EFGH country sites. Secondary Aims 1. Determine the incidence of Shigella medically-attended diarrhea by serotype, severity definition, laboratory method (culture vs. qPCR), age, and by season. 2. Describe the prevalence of resistance to commonly used antibiotics in Shigella isolates in each EFGH country site. 3. Determine the risk of death, hospitalization, persistent diarrhea, diarrhea recurrence, and linear growth faltering in the 3 months following an episode of Shigella medically-attended diarrhea. 4. Compare various severity definitions in their ability to distinguish Shigella from non-Shigella attributable diarrhea and ability to predict risk of death or hospitalization in the subsequent 3 months. 5. Quantify the cost incurred by families and health care systems due to Shigella morbidity and mortality. 6. Identify optimal laboratory methods for Shigella culture by: 1. comparing the isolation rate of Shigella between two transport media for rectal swabs (Cary-Blair and modified Buffered Glycerol Saline \[BGS\]) 2. comparing the isolation rate of Shigella between two fecal sample types (rectal swabs and whole stool) among the subset of children who produced whole stool in The Gambia and Bangladesh country sites.
Interventions
None listed
Sponsors
Aga Khan University
International Centre for Diarrhoeal Disease Research, Bangladesh
University of Maryland, Baltimore
University of Virginia
Asociacion Benefica Prisma
Medical Research Council Unit, The Gambia
Kenya Medical Research Institute
Center for Vaccine Development - Mali
Malawi-Liverpool-Wellcome Trust Clinical Research Programme
Bill and Melinda Gates Foundation
University of Washington
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
6 Months to 35 Months
Healthy volunteers
No
Inclusion criteria
1. Child is 6-35 months of age 2. Primary caregiver and child plan to remain at their current residence for at least the next 4 months 3. Primary caregiver is able to provide informed consent (legal age or emancipated minor) and provides consent within a common language for which translations are available 4. Child presents to health facility with diarrhea (≥3 abnormally loose or watery stools in the previous 24 hours) with or without the presence of blood 5. Child resides within the pre-defined study area 6. Fewer than 4 hours have passed since the child presented to a health facility 7. Diarrhea episode is: * Acute (onset within 7 days of study enrollment) and * Represents a new episode (onset after at least 2 diarrhea-free days) 8. Caregiver is willing to have child participate in follow-up visits at week 4 and month 3 9. Willingness to have samples collected from the child (rectal swabs at enrollment) 10. Site enrollment cap has not been met 11. Child is not being referred to a non-EFGH facility at the time of screening
Exclusion criteria
* Child is \< 6-35 months of age * Child is \> 6-35 months of age * Primary caregiver and child do not plan to remain at their current residence for at least the next 4 months * Primary caregiver is not able to provide informed consent (legal age or emancipated minor) * Primary caregiver does not provide consent within a common language for which translations are available * Child does not present to health facility with diarrhea (≥3 abnormally loose or watery stools in the previous 24 hours) with or without the presence of blood * Child does not reside within the pre-defined study area * 4 or more hours have passed since the child presented to a health facility * Diarrhea episode is not Acute (onset within 7 days of study enrollment) * Diarrhea episode does not represent a new episode (onset after at least 2 diarrhea-free days) * Caregiver is unwilling to have child participate in follow-up visits at week 4 and month 3 * Unwillingness to have samples collected from the child (rectal swabs at enrollment) * Site enrollment cap has been met * Child is being referred to a non-EFGH facility at the time of screening
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Shigella incidence | At enrollment in the study (cross-sectional) | The primary outcome measure is Shigella incidence, defined as incident diarrhea among children enrolled at health clinics attributable to Shigella by microbiological methods (culture or qPCR) divided by the estimated population living in the catchment area. Incidence will be reported as crude incidence as well as adjusted for healthcare seeking and the percentage of children who were enrolled. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cost per episode treated | 3 months | Cost per episode treated will be calculated using the direct and indirect financial costs and total economic costs of illness per outpatient and inpatient episode of Shigella-associated diarrhea from the household and, separately, payer perspectives. |
| Death | 3 months | Death: all cause mortality during follow-up among enrolled children. |
| Hospitalization | 3 months | Hospitalization will be defined as an overnight stay (child was on the ward from at least 12am to 6am) that occurs during follow-up among enrolled children |
| Antimicrobial susceptibility | At enrollment in the study (cross-sectional) | Antimicrobial susceptibility will be computed separately for Ampicillin, Azithromycin, Ceftriaxone, Ciprofloxacin, Nalidixic Acid, Pivmecillinam, and Trimethoprim-Sulfamethoxazole and defined as intermediate or resistant according to the most recent Clinical and Laboratory Standards Institute (CLSI) interpretive standards at the time of data analysis. |
| Diarrhea/dysentery recurrence | 3 months | Diarrhea/dysentery recurrence will be defined as new diarrhea/dysentery episodes (\>48 hours after a diarrhea-free period). |
| Change in linear growth | 3 months | Change in mean length/height-for-age z-score (∆LAZ/∆HAZ) from enrollment to 3 months. The 2006 World Health Organization (WHO) reference population will be used to calculate HAZ from the average of two repeated length/height (cm) measures per child per time point |
| Persistent diarrhea (index episode) | 3 months | Persistent diarrhea will be defined as 14 or more days of diarrhea (starting from the date at which the diarrhea first started (as opposed to date at presentation to an EFGH facility) and concluding at the last day of diarrhea prior to the two consecutive diarrhea-free days concluding the episode. |
Countries
Bangladesh, Kenya, Malawi, Mali, Pakistan, Peru, The Gambia
Outcome results
None listed