This is a Phase II b, double-blind, randomized, placebo-controlled study in healthy adults (age 18-65 years) to evaluate the safety, immunogenicity, different diagnostic tools and efficacy of two doses of ETVAX. Study participants will be recruited among students, and personnel at the University of Helsinki and Helsinki University Hospital and among those responding to recruitment advertisements. To be eligible, the participants have to commit themselves to comply with the study protocol which involves in addition to vaccination, study visits and sampling, and commitment to travel to Grand Popo, Benin and stay there for 12 days. After providing written informed consent, eligible participants will be randomized (ratio 1:1, and block randomization in groups of 6) and immunized with two doses of vaccine or placebo, given 14±7 days apart while in Finland. The last dose of vaccine will be administered at least one week before departure (and no more than 30 days prior to travel) to Benin. Eligible participants will pay four pre-travel visits (V0 + V 1-3) to Aava Travel Clinic / University of Helsinki prior to travel. They will be asked to fill in pre-travel questionnaire latest at visit 1 (Q1) and fill in an Adverse Event Form (AEF1 and AEF2) after each dose, and give blood and fecal samples and saliva before travel. The participants will go together to Benin in groups of 25-35 individuals at a time.~In Benin, the participants will be seen within 48 hours of arrival to the study site in Grand Popo. Once the participants arrive at the study site in Grand Popo, they will be provided with practical information and contact details of the study personnel. They will receive the health card (HC1) and a stool collection kit with instructions.~Diarrhea reporting, stool collection, and stool submission procedures will be reviewed with the study participants. One routine visit at day 4 is planned for review of the participant's health status and collection of a routine stool sample. Other visits will take place when and if the participant gets Travelers Diarrhea (TD) episodes for collection of study specific stool samples and health related information and assessments. If more than one diarrhea episode occurs, 48 diarrhea and symptom (TD defined symptoms) free hours must have passed between the episodes for the new episode to be counted as a separate one. One or two days prior to departure from the Grand Popo site, all participants will have a final review of their HC1s. Health Card ( HC2) will be given. After 1-6 days back in Finland the participant has to give blood and a routine stool sample and they fill in Questionnaire 2 (Q2), HC2 will be reviewed. Approx. 30 days after return to Finland the last stool and blood sample will be collected and the post-travel questionnaire (Q3) filled and HC2 reviewed. Participants who get urinary tract infection will fill in Urinary questionnaire 4 (QU4) form at the time of infection. This follow-up is valid until V5.
This is a Phase II b, double-blind, randomized, placebo-controlled study in healthy adults (age 18-65 years) to evaluate the safety, immunogenicity, different diagnostic tools and efficacy of ETVAX. Participants will travel to Grand Popo, Africa for 12 days. Prior travelling participants will be vaccinated with two doses of vaccine or placebo. Vaccine Preventable Outcome will be identified and then characterized as to incidence, duration, severity and frequency of Moderate or Severe Travellers diarrhea. Health related information and assessments will be recorded during the travel.