Sample size considerations
TB
We considered sample size estimation for the South Africa and Ethiopia sites separately because of the differences in TB epidemiology in the two countries. Sample size calculations were based on the primary outcome which is the clinic-level number of child contacts under age 15 years (Ethiopia) or under 5 years (South Africa) initiating TPT per index patient, compared between the two study arms. We expect there to be a harmonic mean of 51 and 32 diagnosed TB patients per clinic during the study period, in South Africa and Ethiopia respectively. We also expect 20% refusals, withdrawals, or loss to follow-up leading to an average of 40 and 26 TB patients, as reported by the respective TB programs. An estimate of the coefficient of variation (CV) was obtained from a previous contact tracing study in South Africa which was 0.35 [