Using data from a population survey (n = 2119) collected between May to December 2011, we used multinomial regression to examine factors that influence enrolment, controlling for theoretically relevant covariates.
Among vaccinated individuals, the duration time between vaccination and infection (cases) or enrolment (controls) ranged from 35 to 988 days.
All study subjects had been residents of Dharan town for at least 2 years at time of diagnosis (cases) or at time of enrolment (controls).
Setting the follow up time point according to infant age, rather than time since enrolment, controls for the large variability in infant development that might otherwise impact on our results.
We know from our experience and clinic demographics, that we can expect ∼6 patients with newly diagnosed CP in the requisite age group per 3-month period, making possible a design of staggered enrolment of control and intervention groups in an RCT.
This apparent difference was caused by a time lag in the enrolment of controls.
Broadly speaking, during the community engagement processes and the enrolment of controls at the community level there was more space for discussions about genomic aspects of the research than during recruitment of cases in the ward.
A major challenge with case-control studies is the identification and enrolment of suitable control subjects.
To avoid selection bias of positive respondents, we prohibited re-enrolment of controls once they were matched to a case.
Blood collection will be requested at time of enrolment for cases, controls and additional members of control households.
However, those studies that measured costs after enrolment in TB control programs invariably found considerable costs during treatment [ 1, 12- 14].
