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Sociodemographic Characteristics in the Retention of an Infant Cohort in Western Kenya in Preparation for future TB Vaccine Trials. Patience Oduor , G. Oduwo, S.Wandiga, G. Kiringa ,V. Nduba KEMRI/CDC Research and Public Health Collaboration. Third Global TB Forum 25-27 March 2013. Background.
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Sociodemographic Characteristics in the Retention of an Infant Cohort in Western Kenya in Preparation for future TB Vaccine Trials Patience Oduor, G. Oduwo, S.Wandiga, G. Kiringa ,V. Nduba KEMRI/CDC Research and Public Health Collaboration Third Global TB Forum 25-27 March 2013
Background • Kenya is ranked 12th out of the 22 countries with the most TB (WHO 2012 report) • Incidence of TB disease 291/100,000 (WHO 2012 report) • Nyanza Province has greatest TB burden in Kenya • TB notification: 440/100,000 • 20% of all notified TB cases in Kenya • HIV prevalence among TB patients registered with TB program in Nyanza is ~75% (52% nationally)
Background • BCG ( Bacille Calmette Guerin) • is the only licensed TB vaccine available • Is protective against severe forms of TB in childhood but its protection wanes in adolescence and adulthood • There are safety concerns on its use among HIV-infected infants • The risk of severe forms of TB disease is highest in infants and peaks at 2 years, making this age group a prime target for new TB vaccines
Infant Cohort Study (ICS) • Study Design: A prospective epidemiological study • Objective: • To determine, in a population of BCG-vaccinated infants in Western Kenya , at least in the first year of life , the incidence rate of culture –positive (“definitive”)TB • Methods: • 2900 infants were enrolled at home and health facilities • Follow up at six weeks and after every 4 months thereafter at 9 peripheral clinics and at home • TB suspects were identified during follow up visits ,sick visits and routine health records surveillance • TB suspects were admitted at the Case Verification Ward for diagnostic work up
Retention in a vaccine trial • “Retention” - Refers to completion of follow-up visits and procedures as specified in a study protocol • It is defined based on whether participants complete the study exit visit • Critical for safety endpoints • To report the number of adverse events and relatedness to study vaccine • Demonstrate vaccine efficacy: • low retention may show vaccine to be falsely ineffective or effective
Retention strategies in ICS • Tracking migrating participants • Obtaining and updating locator information • Visits alerts by field workers for upcoming visits • Scheduling cards • Provision of ancillary care • Transport reimbursement • Continuous community mobilization including open days • Home visits for those who could not come to the study clinics
Results 1: Retention based on gender Ratio at enrolment Retention rates by gender
Results (2): Retention based on Maternal age P< 0.0001 Ratio at enrolment Retention rates by maternal age
Results (3) :Retention based on Maternal level of education Ratio at enrolment Retention rates
Results (4)Retention based on maternal occupation Ratio at enrolment Retention rates
Challenges in retention • Outmigration • marriage and divorce • cultural norms after delivery • Most people in urban areas do not know their neighbors whereabouts • High mobility of the mothers especially urban areas • Long distances from the health facilities where follow up visits were conducted
Discussion and conclusion • Higher retention rates were observed in babies whose mothers are younger, unoccupied and with primary education • We identified maternal age , level of education and occupation as predictors of study completion • Strategies in future TB vaccine trials should be devised to retain those whose mothers are older, employed and with post primary education so as to bolster retention
Acknowledgements Study participants Community members- Karemo and Boro division KEMRI/CDC Research and Public Health Collaboration AERAS TB GLOBAL VACCINE FOUNDATION KNCV (Dutch TB Foundation) EDCTP Ministry of Health- GoK