Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings
Abstract Typhoidal Salmonella is a major global problem affecting more than 12 million people annually. Controlled human infection models (CHIMs) in high-resource settings have had an important role in accelerating the development of conjugate vaccines against Salmonella Typhi. The typhoidal Salmone...
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| Format: | Article |
| Language: | English |
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BMC
2019-12-01
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| Series: | Trials |
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| Online Access: | https://doi.org/10.1186/s13063-019-3844-z |
| _version_ | 1819077463798448128 |
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| author | Meriel Raymond Malick M. Gibani Nicholas P. J. Day Phaik Yeong Cheah |
| author_facet | Meriel Raymond Malick M. Gibani Nicholas P. J. Day Phaik Yeong Cheah |
| author_sort | Meriel Raymond |
| collection | DOAJ |
| description | Abstract Typhoidal Salmonella is a major global problem affecting more than 12 million people annually. Controlled human infection models (CHIMs) in high-resource settings have had an important role in accelerating the development of conjugate vaccines against Salmonella Typhi. The typhoidal Salmonella model has an established safety profile in over 2000 volunteers in high-income settings, and trial protocols, with modification, could be readily transferred to new study sites. To date, a typhoidal Salmonella CHIM has not been conducted in a low-resource setting, although it is being considered. Our article describes the challenges posed by a typhoidal Salmonella CHIM in the high-resource setting of Oxford and explores considerations for an endemic setting. Development of CHIMs in endemic settings is scientifically justifiable as it remains unclear whether findings from challenge studies performed in high-resource non-endemic settings can be extrapolated to endemic settings, where the burden of invasive Salmonella is highest. Volunteers are likely to differ across a range of important variables such as previous Salmonella exposure, diet, intestinal microbiota, and genetic profile. CHIMs in endemic settings arguably are ethically justifiable as affected communities are more likely to gain benefit from the study. Local training and research capacity may be bolstered. Safety was of primary importance in the Oxford model. Risk of harm to the individual was mitigated by careful inclusion and exclusion criteria; close monitoring with online diary and daily visits; 24/7 on-call staffing; and access to appropriate hospital facilities with capacity for in-patient admission. Risk of harm to the community was mitigated by exclusion of participants with contact with vulnerable persons; stringent hygiene and sanitation precautions; and demonstration of clearance of Salmonella infection from stool following antibiotic treatment. Safety measures should be more stringent in settings where health systems, transport networks, and sanitation are less robust. We compare the following issues between high- and low-resource settings: scientific justification, risk of harm to the individual and community, benefits to the individual and community, participant understanding, compensation, and regulatory requirements. We conclude that, with careful consideration of country-specific ethical and practical issues, a typhoidal Salmonella CHIM in an endemic setting is possible. |
| first_indexed | 2024-12-21T18:57:36Z |
| format | Article |
| id | doaj.art-cc1904c956d64389b57f53471811edf6 |
| institution | Directory Open Access Journal |
| issn | 1745-6215 |
| language | English |
| last_indexed | 2024-12-21T18:57:36Z |
| publishDate | 2019-12-01 |
| publisher | BMC |
| record_format | Article |
| series | Trials |
| spelling | doaj.art-cc1904c956d64389b57f53471811edf62022-12-21T18:53:34ZengBMCTrials1745-62152019-12-0120S21710.1186/s13063-019-3844-zTyphoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settingsMeriel Raymond0Malick M. Gibani1Nicholas P. J. Day2Phaik Yeong Cheah3Oxford Vaccine Group Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), Churchill HospitalOxford Vaccine Group Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), Churchill HospitalMahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityMahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityAbstract Typhoidal Salmonella is a major global problem affecting more than 12 million people annually. Controlled human infection models (CHIMs) in high-resource settings have had an important role in accelerating the development of conjugate vaccines against Salmonella Typhi. The typhoidal Salmonella model has an established safety profile in over 2000 volunteers in high-income settings, and trial protocols, with modification, could be readily transferred to new study sites. To date, a typhoidal Salmonella CHIM has not been conducted in a low-resource setting, although it is being considered. Our article describes the challenges posed by a typhoidal Salmonella CHIM in the high-resource setting of Oxford and explores considerations for an endemic setting. Development of CHIMs in endemic settings is scientifically justifiable as it remains unclear whether findings from challenge studies performed in high-resource non-endemic settings can be extrapolated to endemic settings, where the burden of invasive Salmonella is highest. Volunteers are likely to differ across a range of important variables such as previous Salmonella exposure, diet, intestinal microbiota, and genetic profile. CHIMs in endemic settings arguably are ethically justifiable as affected communities are more likely to gain benefit from the study. Local training and research capacity may be bolstered. Safety was of primary importance in the Oxford model. Risk of harm to the individual was mitigated by careful inclusion and exclusion criteria; close monitoring with online diary and daily visits; 24/7 on-call staffing; and access to appropriate hospital facilities with capacity for in-patient admission. Risk of harm to the community was mitigated by exclusion of participants with contact with vulnerable persons; stringent hygiene and sanitation precautions; and demonstration of clearance of Salmonella infection from stool following antibiotic treatment. Safety measures should be more stringent in settings where health systems, transport networks, and sanitation are less robust. We compare the following issues between high- and low-resource settings: scientific justification, risk of harm to the individual and community, benefits to the individual and community, participant understanding, compensation, and regulatory requirements. We conclude that, with careful consideration of country-specific ethical and practical issues, a typhoidal Salmonella CHIM in an endemic setting is possible.https://doi.org/10.1186/s13063-019-3844-zResearch ethicsControlled human infection modelsLow-resource settingsTyphoidal Salmonella |
| spellingShingle | Meriel Raymond Malick M. Gibani Nicholas P. J. Day Phaik Yeong Cheah Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings Trials Research ethics Controlled human infection models Low-resource settings Typhoidal Salmonella |
| title | Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings |
| title_full | Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings |
| title_fullStr | Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings |
| title_full_unstemmed | Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings |
| title_short | Typhoidal Salmonella human challenge studies: ethical and practical challenges and considerations for low-resource settings |
| title_sort | typhoidal salmonella human challenge studies ethical and practical challenges and considerations for low resource settings |
| topic | Research ethics Controlled human infection models Low-resource settings Typhoidal Salmonella |
| url | https://doi.org/10.1186/s13063-019-3844-z |
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