Study design
diarrhoea, ETEC, HUS, ®
MAY, SECONDARY, RECRUITMENT, WEST
OEV123 was a double-blinded, randomized placebo-controlled trial conducted between 31 May 2017 and 15 April 2019 (recruitment 31 May 2017 to 7 February 2019; follow-up until 15 April 2019) at Meilahti Vaccine Research Center, MeVac, HUS Helsinki University Hospital and University of Helsinki, and at two other centres, the Aava Travel Clinic, Helsinki and Villa Karo Research Center, VKRC, in Grand Popo, Benin, West Africa. The volunteers did not receive any payment, but their travel expenses were partly subsidized by the sponsor. Every 2 weeks a new group departed to Benin, the group sizes varying according to the volunteers’ availability. The protocol was approved by the Ethics Committee of HUS (HUS/2231/2016) and the Finnish Medicines Agency (EudraCT 2016-002690-35). The study was recorded in Finnish adults (18–65 years of age) were randomized 1:1 to receive ETVAX® or placebo (computed block randomization within the eCRF system in groups of six). The volunteers were asked to provide stool and blood samples and fill in health cards and questionnaires at given time points before, during and after their 12-day visit to Benin (Flow chart of the study conduct of the double-blinded randomized controlled trial on ETVAX®, a multivalent oral vaccine against ETEC, amongst Finnish travellers visiting Grand Popo, Benin, West Africa. (A) Summary of initial study design and objective; (B) flow chart of data presented in the present report. *Main reasons for screening failures: 26/33 (76%) changed their mind after providing written informed consent and 3/33(9%) realized that they would not, after all, be available for all the planned follow-up visits.The primary objectives of the OEV123 study were to assess the safety and immunogenicity of ETVAX® and to elucidate the difference between culture-based and non-culture-based diagnostic tools in identification of ETEC. The secondary objectives were to evaluate both efficacy and immunological markers of protection, and to further explore the laboratory tools.To meet additional exploratory objectives, we expanded our core study OEV123 by conducting further sampling and collecting information by questionnaires (those data are not included here). As a change to the initial study design with 800 volunteers, the recruitment was discontinued slightly before reaching this number. We made the decision because of resource constraints and a far greater diarrhoea incidence than anticipated in the initial power calculations.