Enterotoxigenic E. coli (ETEC) diarrhoea Infections and Infestations
Conditions
Interventions
One oral dose of TEV will be given to healthy adult Swedes previously vaccinated with TEV ± dmLT adjuvant (10 µg) or age-matched non-vaccinated subjects. The vaccine consists of approximately 8x10e10
Sponsors
Gothenburg University Vaccine Research Institute (GUVAX) (Sweden)
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Male or female aged 18-47 years 2. Healthy constitution as established by medical history, medical examination and clinical chemistry and haematology testing 3. Willing and able to communicate with the investigators/physicians and understand the requirements of the study 4. Give written informed consent to participate 5. Sexually active females should, unless being menopausal, agree to use reliable contraception during the study as assessed by the investigator/physician, and should have a negative urine pregnancy test at screening and also negative urine pregnancy tests before vaccination. 6. For recruitment to group A: has never received any ETEC vaccine For recruitment to group B: has received two doses of TEV in the OEV-121 study For recruitment to group C: has received two doses of TEV + 10 µg dmLT in the OEV-121 study
Exclusion criteria
Exclusion criteria: 1. 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. 2. Gastroenteritis within two weeks prior to vaccination 3. Antibiotic therapy within six weeks prior to vaccination 4. Known hepatitis A, B, C and/or HIV infection 5. Concomitant intake of immune-modulating drugs during the study period or less than three months prior to the first immunization 6. Psychiatric symptoms and treatments during the last year deemed by the investigator/physician to be relevant for participation in the OEV-121A study. 7. Intends to receive any other vaccine during the study period, or within two weeks prior to trial vaccination 8. Any known hypersensitivity to any ingredient in the vaccines 9. Has received Dukoral or any other ETEC vaccine than the TEV 10. Brought up in ETEC-endemic areas (e.g., Central and South America, Caribbean, most countries in Asia, Africa, etc) 11. Has travelled to ETEC-endemic areas within the last 3 years or spent > two months in ETEC-endemic areas during the last 10 years 12. Known or suspected history of drug, chemical or alcohol abuse, as deemed by the investigator/physician 13. Receipt of any other investigational product in the month before study entry or during the study deemed by the investigator/physician to be relevant for the OEV-121 study 14. Concomitant participation in any other clinical study deemed by the investigator/physician to be relevant for the OEV-121A study 15. Blood donation less than two weeks before immunization until one month after immunization 16. Females who are pregnant 17. Females who are nursing 18. Unable to participate in all study visits 19. Any condition or circumstance which would make the subject unsuitable for participation in the study in the opinion of the investigator/physician
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| To determine if primary vaccination with an inactivated tetravalent ETEC vaccine (TEV), given in two oral doses two weeks apart ± dmLT adjuvant to adult volunteers, has induced immunological memory responses against toxin (LTB) and colonization factor (CF) vaccine antigens. Memory will be assessed as accelerated, higher and/or more frequent intestinally derived immune responses (antibodies in lymphocyte supernatants; ALS) to a single oral booster dose of TEV given to primed subjects vaccinated 1-2 years before than to a single dose of TEV given to naïve subjects. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. To evaluate the safety of a single booster dose of TEV given to subjects previously vaccinated with a primary 2-dose series of TEV alone or TEV + dmLT and to further evaluate the safety of a single dose of TEV given to naive subjects. 2. To evaluate if TEV previously given in two oral doses ± dmLT has induced systemic immunological memory as measured by accelerated and/or higher and/or more frequent serum IgA and /or IgG antibody responses against LTB to a single oral dose of TEV given after 1-2 years than to a single dose of TEV given to naive volunteers. 3. To evaluate if the avidity of the antibody responses induced by the late booster immunization with TEV is higher than the avidity of the responses induced by the first or the second primary vaccinations or after a single dose given to naive subjects. 4. To evaluate if primary vaccinations with TEV alone and/or TEV + dmLT have induced vaccine-specific memory B-cell responses that are detectable in the circulation (using polyclonal B-cell stimulation methods); this includes evaluating if there is a relationship between circulating memory B-cell responses prior to vaccination and memory antibody responses to a single booster dose determined by ALS analyses. 5. To evaluate if primary vaccination with TEV + dmLT adjuvant has induced accelerated, higher and/or more frequent immunological memory responses than priming with TEV. Gastrointestinal and systemic adverse events will be assessed post-vaccination through day 7 using physical examination, vital signs and clinical laboratory tests, diary cards and interviews. | — |
Countries
Sweden
Outcome results
None listed