‘An Electronic Surveillance System for Intensified TB Case Detection in an Adolescent Cohort Study, In Preparation for Future Tuberculosis Vaccine Trials in Western Kenya'.

Abstract

Introduction The age specific incidence of tuberculosis (TB) in developing countries gradually rises in adolescence, making adolescents a good target group for introduction of new TB vaccines. Phase III TB vaccine trials require solid measurable endpoints. We sought to do electronic surveillance in addition to scheduled active follow-up visits to maximize TB case finding. Methods The study area is under a continuous Health and Demographic Surveillance System. After enrolment, passively detected TB cases listed in TB registers were searched and matched with Health and Demographic Surveillance System registers to see if they resided in the same compounds as study participants. If so, these were contacted for investigation as TB suspects. TB cases aged 12-18 years were also searched in the study database to verify whether they were study participants. TB laboratory and chest x-ray records were searched to identify potential TB suspects. Results During follow-up 8 TB cases were identified, the person time accumulated by all 5004 subjects was 6002.4 years with a corresponding incidence density of 2.0 (95% CI: 1.14-3.52) per 1000 person years. In addition, 5 TB cases were identified through the surveillance system accumulating 5.36 years with a corresponding incidence density of 0.8 (95% CI: 0.3-2.0) per 1000 person years. Conclusion The results of identification of TB cases through electronic surveillance indicate this is a useful approach that should be further explored. The additional cases yielded by electronic surveillance might help downward revision of required samples sizes or help in shortening follow-up time if TB cases are found more quickly.