Funding for this research was provided by:
Directorate-General for International Cooperation and Development (Framework Agreement 4 with ITM Antwerp, 2017–2021)
Received: 16 February 2021
Accepted: 5 May 2021
First Online: 10 May 2021
: The protocol was approved by the Institutional Review Board of the Institute of Tropical Medicine, Antwerp, Belgium (ref. 1422/20). Distributors freely accepted to be assessed, provided that their confidentiality was protected by not making them identifiable.
: Not applicable.
: RR is the Chairperson of the Institutional Review Board of the Institute of Tropical Medicine Antwerp, Belgium, which reviewed and approved the study protocol. She did not participate in the review of this research protocol, which was coordinated by the vice chair.