Establishing the Optimal Dose of Therapeutic Zinc Supplementation for the Treatment of Acute Diarrhea in Under Five Children - a Dose Response Trial in a South Asian and a Sub-Saharan African Setting

Diarrhoea continues to be a major cause of child deaths. Current treatment of acute watery diarrhoea includes oral rehydration solution (ORS), zinc and continued feeding. The use of zinc is based on a number of studies that showed that zinc reduces the duration and severity of diarrhoea. The recommended dose of zinc in 6-59 month old children is 20mg/day for 10-14 days. This dose is associated with an increased risk of vomiting. No dosing studies are available to determine the optimal dose of zinc, which while maintaining the benefits also has a low risk of vomiting.

The investigators will conduct a double-blind randomized controlled trial of three doses of zinc (20mg/day, 10mg/day and 5mg/day) in two settings - one in Sub-Saharan Africa and the other in South Asia. The study population will be 4500 children with diarrhoea of less than 72 hours duration who are aged 6-59 months. They will be recruited from outpatient health facilities. All enrolled children will receive ORS and continued feeding as recommended by the World Health Organization. Those allocated to the standard zinc dose will receive an oral dispersible tablet with 20mg zinc daily for 14 days. Those allocated to lower dose zinc will receive identical tablets with either 10mg or 5mg zinc daily for 14 days. Enrolled children will be followed by until recovery from diarrhoea or 15 days after enrolment, whichever is later. In addition, study children will be assessed again at thirty (30), forty-five (45), and sixty (60) days to estimate impact on post illness outcomes. Primary outcomes will be mean duration of diarrhoea, proportion of episodes that last longer than 5 days, mean number of stools and proportion of children with vomiting.