Regimens of Ivermectin for Scabies Elimination: a cluster randomised non-inferiority trial of one versus two doses of ivermectin for the control of scabies using a mass drug administration strategy.

This study is a community-based study of mass drug administration (MDA). All community members of selected villages are eligible for participation and all community members who have provided consent are able to be included. Treatment will be offered to all consenting community members, regardless of scabies diagnosis, who do not meet the exclusion criteria for treatment: - Allergy to any of the components of the allocated drug regimen, - Currently on, or has taken ivermectin in the previous 7 days, - Has had topical 5% permethrin applied within previous 7 days, - Refusal to take treatment, - Considered by study nurses to be too ill for treatment This study investigates the efficacy of two alternative MDA strategies of oral ivermectin for scabies control, namely one dose (Group 1) and two doses (Group 2). 1. Group 1 - Oral ivermectin-based MDA (single dose): Participants will be offered 1 dose of oral ivermectin at 200ug/kg unless contra-indicated. Ivermectin will be replaced by topical permethrin cream in "ivermectin contraindication" groups (see below) as per guidelines for onchocerciasis programmes and product information (Onchocerciasis and Its Control, 1995, Report of a WHO Expert Committee on Onchocerciasis Control, World Health Organisation; Product Information Iver P Ivermectin 3mg tablet, 2015, Elea Argentina). No treatment will be given to participants who are considered by the study nurse to be extremely ill as they will be unable to provide consent. 2. Group 2 - Oral ivermectin based MDA (two-doses): Participants will be offered the first dose of MDA treatment as in the single dose group, and then a second dose 7 to 14 days later, identical to the first. Contra-indication guidelines will be followed as per group 1. Ivermectin is a registered, routinely manufactured and marketed drug produced respectively by Elea Laboratories. The dose of ivermectin will be determined according to body weight and/or height, and treatment will be administered under direct supervision before participants leave the clinic. The recommended dose for scabies is 200 µg/kg. The dose range of 160-250 µg/kg is being used so the tablets can be cut evenly for distribution. The weight range used in this study is narrower than that recommended on the Product Information booklet so that a more accurate dose equivalent to 200 µg/kg can be delivered. The ivermectin dosage per weight for scabies MDA (dose 1 and dose 2) will be as follows: 15-18 kg 3.0 mg 19-27 kg 4.5 mg 28-36 kg 6.0 mg 37-55 kg 9.0 mg 56-74 kg 12.0 mg 75-100 kg 15.0 mg >100kg 18.0 mg Ivermectin will be replaced by topical permethrin cream in the following cases: " pregnant women " mothers nursing infants during the first week of life " children under 12.5kg or 90cm Any medication that participants are taking will be cross checked against the list of medications that interact with ivermectin and are contraindicated. All participants will be screened for contraindications for ivermectin. Participants will be asked whether they think they are pregnant and/or breastfeeding. If a participant is pregnant or unsure if pregnant, topical permethrin cream will be offered instead of oral ivermectin. Children under 12.5kg / 90cm will be offered permethrin cream. Participants with neurologic diseases such as Parkinson's Disease or cerebral palsy, and people taking medication that is metabolised by the cytochrome p450 pathway will be offered permethrin cream. Any medication that participants are taking will be cross checked against the list of medications that interact with ivermectin or permethrin and are contraindicated. If a participant is allergic or hypersensitive to any component of ivermectin, permethrin or crotamiton, that medication will not be offered.