Population differences in vaccine responses (POPVAC): scientific rationale and cross-cutting analyses for three linked, randomised controlled trials assessing the role, reversibility and mediators of immunomodulation by chronic infections in the tropics

Autor: Gyaviira Nkurunungi, Ludoviko Zirimenya, Agnes Natukunda, Jacent Nassuuna, Gloria Oduru, Caroline Ninsiima, Christopher Zziwa, Florence Akello, Robert Kizindo, Mirriam Akello, Anne Wajja, Henry Luzze, Stephen Cose, Alison M Elliott, Rebecca Amongin, Beatrice Nassanga, Irene Nambuya, Prossy Kabuubi, Emmanuel Niwagaba, Grace Kabami, Helen Akurut, Alex Mutebe, Milly Namutebi, Caroline Onen, Esther Nakazibwe, Josephine Tumusiime, Susan Amongi, Moses Sewankambo, Denis Nsubuga, Samuel Kiwanuka, Fred Kiwudhu, David Abiriga, Moses Kizza, Samsi Nansukusa, Hermelijn Smits, Maria Yazdanbakhsh, Govert van Dam, Paul Corstjens, Sarah Staedke, James Kaweesa, Edridah Tukahebwa, Elly Tumushabe
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: BMJ Open, Vol 11, Iss 2 (2021)
ISSN: 2044-6055
Popis: Introduction Vaccine-specific immune responses vary between populations and are often impaired in low income, rural settings. Drivers of these differences are not fully elucidated, hampering identification of strategies for optimising vaccine effectiveness. We hypothesise that urban–rural (and regional and international) differences in vaccine responses are mediated to an important extent by differential exposure to chronic infections, particularly parasitic infections.Methods and analysis Three related trials sharing core elements of study design and procedures (allowing comparison of outcomes across the trials) will test the effects of (1) individually randomised intervention against schistosomiasis (trial A) and malaria (trial B), and (2) Bacillus Calmette-Guérin (BCG) revaccination (trial C), on a common set of vaccine responses. We will enrol adolescents from Ugandan schools in rural high-schistosomiasis (trial A) and rural high-malaria (trial B) settings and from an established urban birth cohort (trial C). All participants will receive BCG on day ‘0’; yellow fever, oral typhoid and human papilloma virus (HPV) vaccines at week 4; and HPV and tetanus/diphtheria booster vaccine at week 28. Primary outcomes are BCG-specific IFN-γ responses (8 weeks after BCG) and for other vaccines, antibody responses to key vaccine antigens at 4 weeks after immunisation. Secondary analyses will determine effects of interventions on correlates of protective immunity, vaccine response waning, priming versus boosting immunisations, and parasite infection status and intensity. Overarching analyses will compare outcomes between the three trial settings. Sample archives will offer opportunities for exploratory evaluation of the role of immunological and ‘trans-kingdom’ mediators in parasite modulation of vaccine-specific responses.Ethics and dissemination Ethics approval has been obtained from relevant Ugandan and UK ethics committees. Results will be shared with Uganda Ministry of Health, relevant district councils, community leaders and study participants. Further dissemination will be done through conference proceedings and publications.Trial registration numbers ISRCTN60517191, ISRCTN62041885, ISRCTN10482904.
Databáze: OpenAIRE