Inclusion Criteria:  Male or female aged 18-50 years, inclusive at the time of signing the informed consent. Healthy constitution as established by medical history and physical examination. Willing and able to give written informed consent for participation in the study. Able to comply with study activities, as judged by the Investigator. Female Participants: Women of child-bearing potential (for definition see Section 9.3.6 in the protocol): Have to agree to use an acceptable birth control method during participation in the investigation (see Section 9.3.6). A negative pregnancy test (beta human chorionic gonadotropin dipstick test in urine) at Visit 2/Day 1 will be required. Male Participants: Have to agree to remain abstinent (refrain from heterosexual intercourse) or use a condom, and agreement to refrain from donating sperm, as defined in Section 9.3.6  Exclusion criteria  An acute or chronic medical condition that, in the opinion of the investigator/physician, would render ingestion of the investigational products unsafe or would interfere with the evaluation of responses. This includes, but is not limited to gastrointestinal diseases, and autoimmune diseases. Current malignancy or history of malignancy during the last five years, based on anamnesis. Gastroenteritis within two weeks prior to vaccination. Regular use of laxatives, antacids or other agents that lower stomach acidity. Any planned major surgery during the duration of the study. After 10 minutes supine rest, any vital signs outside the following ranges: Systolic BP > 160 mm Hg Diastolic BP > 100 mm Hg Heart rate < 40 or >85 beats per minute Antibiotic therapy within two weeks prior to the vaccination. Known Hepatitis A, B, C, and/or HIV infection. Concomitant intake of immunomodulating drugs during the study period or less than 3 months prior to the first immunization. Local anti-histamine treatment is however allowed. Any other significant medical conditions (e.g. poorly controlled psychiatric condition) judged by the Investigator to preclude entry. Intends to receive any other vaccine during the study period, or within two weeks prior to trial vaccination. Has previously received Dukoral or any type of ETEC or cholera vaccines. Brought up in ETEC-endemic areas (e.g., urban and rural areas of Central and South America, Caribbean, most countries in Asia, Africa, etc.). Has travelled to ETEC-endemic areas within the last 3 years OR spent > two months in ETEC endemic areas during the last 10 years. Intends to travel to ETEC endemic countries during the study period. Known or suspected history of drug, chemical or alcohol abuse, as deemed by the investigator/physician. History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity, as judged by the Investigator, or history of hypersensitivity to drugs with a similar chemical structure or class to ETVAX®. Participation in any other clinical study that included drug treatment with the last administration within the past 3 months prior to administration of study treatment in this study. Patients consented and screened but not dosed in previous clinical studies are not excluded. Concomitant participation in any other clinical study. Females who are pregnant as determined by urine test at inclusion and prior to each vaccination. Females who are nursing. Unable to participate in all study visits. Any condition or circumstance which would make the subject unsuitable for participation in the study in the opinion of the investigator/physician.