The PREVAC-UP trial consists in a long term follow-up of patients included in the PREVAC trial to determine (i) the long-term immunogenicity and safety and (ii) durability of humoral and cellular immune responses of Ebola vaccine regimes over 60 months. In this postdoc, we propose to address these two question using mathematical modeling and statistics.

The main objective of this postdoc position will be to use the data gathered through the PREVAC/PREVAC-UP trials to build and fit a model of the immune response to the Ebola vaccine in order to better characterize the response (duration) and better understand the mechanism of its establishment. Model estimation will be performed using maximum likelihood approach as implementer with the SAEM algorithm, for example in the MONOLIX software of the Lixoft suite. Methodological development will consist in building a series of model building strategies.

Modeling will be inspired from work previously published by the team:
[1] Pasin, C., Balelli, I., Van Effelterre, T., Bockstal, V., Solforosi, L., Prague, M., ... & Thiébaut, R. (2019). Dynamics of the humoral immune response to a prime-boost Ebola vaccine: quantification and sources of variation. Journal of virology, 93(18), e00579-19.
[2] Balelli, I., Pasin, C., Prague, M., Crauste, F., Van Effelterre, T., Bockstal, V., ... & Thiébaut, R. (2020). A model for establishment, maintenance and reactivation of the immune response after vaccination against Ebola virus. Journal of Theoretical Biology, 495, 110254.

See this book for an introduction to mechanistic model:
[3] Lavielle, M. (2014). Mixed effects models for the population approach: models, tasks, methods and tools. CRC press.

The Prevac trial is described here:
[4] Badio, M., Lhomme, E., Kieh, M., Beavogui, A. H., Kennedy, S. B., Doumbia, S., ... & Yazdanpanah, Y. (2021). Partnership for Research on Ebola VACcination (PREVAC): protocol of a randomized, double-blind, placebo-controlled phase 2 clinical trial evaluating three vaccine strategies against Ebola in healthy volunteers in four West African countries. Trials, 22(1), 1-15.