Ethical considerations
The study obtained ethical approval from the Medical Research Coordinating Committee (MRCC, Tanzania) with approval number NIMR/HQ/R.8a/Vol.IX/3291 and NIMR/HQ/R.8c/Vol.I/1652 (for extension) and regulatory approval from the Tanzania Medicines and Medical Devices Authority (TMDA) with approval number TMDA0019/CTR/0018/03. Informed consent was obtained from parents /guardian of schoolchildren involved in effectiveness evaluation. The study is registered on clinicaltrials.gov with registration number NCT04245033.