Research

Mathematical Modeling of biological systems

Research interests, selected publications, the full list of publications and preprints, talks and posters, and theses.



Research Overview

My research focuses on developing mathematical theory for studying complex biological systems, with emphasis on quantitative frameworks that bridge mathematical analysis and biological insight.

A central theme of my work is infectious disease modeling across biological scales. This includes developing data-driven mathematical frameworks for understanding disease dynamics at the population level, characterizing within-host pathogen dynamics, and modeling the kinetics of immune responses induced by infection. I am particularly interested in vaccine-induced immune responses, including the dynamics of humoral immunity, germinal center reactions, and the interplay between innate and adaptive immune responses across a range of diseases.

I also develop quantitative systems pharmacology (QSP) models to investigate biological systems in the context of drug development, linking mechanistic models of biological processes to pharmacokinetic and pharmacodynamic outcomes.

A second major focus of my research is first-passage processes and reaction-diffusion systems for passive and active biological systems. I am particularly interested in extending reaction-diffusion frameworks to infectious disease modeling, developing and analyzing mathematical models that capture not only disease transmission dynamics but also the spatial and environmental factors that shape disease spread.

Mathematical and Computational Methods: I develop models using ordinary differential equations (ODEs), partial differential equations (PDEs), stochastic simulations, and agent-based modeling. I also apply statistical and machine learning methods for model calibration, parameter estimation, and data analysis. My analytical toolkit includes dynamical systems theory, perturbation theory, asymptotic analysis, and biophysical techniques. For numerical analysis, I employ finite difference, finite element, and closest point methods.

Below are my research areas:

Reaction-Diffusion Systems and Multiscale Disease Modeling

Reaction-diffusion systems have been a cornerstone of mathematical biology, providing a powerful framework for studying spatial and temporal dynamics in biological systems, from Turing pattern formation and chemical signaling to the spread of invasive species and infectious diseases. In my research, I employ reaction-diffusion frameworks to study intercellular signaling and communication, as well as the spatial spread of infectious diseases through populations. A growing focus of my work is the development of multiscale reaction-diffusion frameworks that integrate disease dynamics across biological scales, including coupling within-host pathogen dynamics to population-level transmission, incorporating host movement and spatial heterogeneity into epidemic models, modeling cross-species and zoonotic transmission in coupled human and animal populations, and capturing environmental transmission pathways and vector-borne disease dynamics. Through these research directions, I aim to develop mathematically rigorous and biologically realistic frameworks that provide quantitative tools for understanding disease spread and informing public health intervention design.

Signalling compartments synchronizing through a shared bulk-diffusion field.

Selected articles and preprints on reaction-diffusion systems

  1. Oscillatory instabilities in dynamically active signalling compartments coupled via bulk diffusion in a 3-D spherical domain. Preprint

    Physica D: Nonlinear Phenomena 476 (2025) 134645  DOI

    Sarafa A. Iyaniwura and Michael J. Ward.

  2. Synchronous Oscillations for a Coupled Cell-Bulk PDE-ODE model with Localized Cells on R^2. Preprint

    Journal of Engr. Math, Vol. 127, No. 18, 2021.  DOI

    Sarafa A. Iyaniwura, Jia Guo and Michael J. Ward.

First Passage Time (FPT) Theory

First-passage time (FPT) phenomena provide valuable insights into the timing and likelihood of rare or critical events in stochastic systems, with broad applications across biology, immunology, and disease dynamics. The mean first-passage time (MFPT) is a fundamental tool for quantifying the expected time for a random process to reach a target state for the first time, with important applications ranging from molecular transport and receptor-ligand binding kinetics to immune cell search processes, pathogen clearance, and the timing of disease outbreak initiation. My work focuses on developing analytical and computational frameworks for studying FPT phenomena in passive and active stochastic systems, with applications to both physical and biological settings. On the biological and immunological side, this includes modeling the time for immune cells such as T cells and dendritic cells to locate rare antigen-presenting targets in lymphoid tissues, quantifying the search time of antibodies for pathogen epitopes, and characterizing stochastic timing in early infection dynamics and within-host immune responses. Through rigorous mathematical analysis and computation, I aim to develop theoretical frameworks that provide mechanistic insights into FPT behavior in complex and constrained biological environments, ultimately informing our understanding of how timing shapes outcomes in immunological and disease processes.

A particle escaping a reflecting disk, hunted by a rotating absorbing trap.

Selected articles and preprints on MFPT theory

  1. Asymptotic analysis and simulation of mean first passage time for active Brownian particles in 1-D. Preprint

    SIAM Journal on Applied Mathematics, 2024. Vol. 84, No. 3, pp 1079-1095  DOI.

    Sarafa A. Iyaniwura and Zhiwei Peng.

  2. Optimization of the Mean First Passage Time in Near-Disk and Elliptical Domains in 2-D with Small Absorbing Traps Preprint

    SIAM Review, 2021, Vol. 63, No. 3 : pp. 525-555 .  DOI

    Sarafa A. Iyaniwura, Tony Wong, Colin B. Macdonald and Michael J. Ward.

Infectious Disease Modeling and Immunology

Population-Level Infectious Disease Modeling

My research in population-level disease modeling focuses on developing data-driven mathematical frameworks to study the transmission dynamics of infectious diseases, including HIV, malaria, cholera, and COVID-19, evaluate the effectiveness of public health interventions, and inform policy decisions. A central theme of this work is understanding how adaptive human behaviour, including vaccine hesitancy, anti-authority resistance, and adherence to non-pharmaceutical interventions, shapes disease spread in a population. I am also committed to translating mathematical insights into actionable public health guidance, providing modeling support to public health officials and policymakers. During the COVID-19 pandemic, I contributed to this effort as a member of the COVID-19 PWIAS Working Groups: Mathematical Modeling to Understand COVID-19 Epidemic Dynamics in British Columbia.

Age-structured COVID-19 model schematic

Within-Host Infectious Disease Dynamics and Immunology

My research in within-host modeling focuses on developing mathematical frameworks to study the evolution of viruses, including HIV, SARS-CoV-2, HBV, HCV, and Ebola, within an infected host. Key areas of interest include characterizing viral infection kinetics and modeling the dynamics of innate and adaptive immune responses, including B and T cell dynamics during infection and vaccination. My current research at Fred Hutchinson Cancer Center focuses on developing a quantitative framework for understanding B cell dynamics during vaccine-induced humoral immune responses, with direct application to studying and optimizing germline-targeting and sequential immunization strategies for HIV vaccine development. I also develop quantitative systems pharmacology (QSP) models to support drug development, providing mathematical frameworks for evaluating antiviral drug efficacy, optimizing dosing strategies, and identifying therapeutic targets.

Within-host viral kinetics fit for an individual patient

Susceptible → Infected → Recovered: individuals flowing through a population-level epidemic model.

Selected articles and preprints on infectious disease modeling and analysis

  1. A multiscale model of the action of a capsid assembly modulator for the treatment of chronic hepatitis B Preprint

    PLoS Computational Biology 21(5): e1012322.  DOI

    Sarafa A. Iyaniwura, Tyler Cassidy, Ruy M. Ribeiro, and Alan S. Perelson

  2. The kinetics of SARS-CoV-2 infection based on a human challenge study

    PNAS 2024, Vol. 121, No. 46: 121(46)e2406303121.  DOI

    Sarafa A. Iyaniwura, Ruy M. Ribeiro, Carolin Zitzmann, Tin Phan, Ruian Ke, and Alan S. Perelson

List of all publications and preprints

  1. Editorial: Mathematical modeling and data analysis in infectious diseases Preprint

    Submitted to Frontiers in Public Health - Infectious Diseases: Epidemiology and Prevention (2026)  DOI. (Under review)

    Andrew Omame, Yanyu Xiao, Qing Han, and Sarafa A. Iyaniwura

  2. The magnitude of early hepatitis B RNA and DNA declines directly inform capsid assembly modulator effectiveness Preprint

    Submitted to mBio (2026)  DOI. (Under review)

    Tyler Cassidy, Sarafa A. Iyaniwura, Ruy M. Ribeiro, and Alan S. Perelson

  3. Mathematical Representation of Adaptive Human Behavior in Mechanistic Epidemic Models: A Systematic Review Preprint

    Submitted to Plos Comp. Bio. (2026)  DOI. (Under review)

    Adeniyi Ebenezer, Sherif Eneye Shuaib, Sarafa A. Iyaniwura, Qing Han, Amy Veprauskas, and Jude D. Kong

  4. Mean first passage time of chiral active Brownian particles Preprint

    Submitted to Soft Matter (2026)  DOI. (In press)

    Sarafa A. Iyaniwura, Mingfeng Qiu, and Zhiwei Peng

  5. Splitting probabilities of confined chiral active Brownian particles Preprint

    New J. Phys. 28 (2026) 054401  DOI.

    Sarafa A. Iyaniwura and Zhiwei Peng

  6. A multiscale framework integrating within-host infection kinetics with airborne transmission dynamics Preprint

    Submitted to SIAM Jounral of Applied Mathematics, 2025  DOI.

    Andrew Omame and Sarafa A. Iyaniwura

  7. Mean first passage time of active Brownian particles in two dimensions Preprint

    New J. Phys. 27(2025) 104401  DOI.

    Sarafa A. Iyaniwura and Zhiwei Peng

  8. Inheritance of intracellular viral RNA in a multiscale model of hepatitis C infection Preprint

    SIAM Jounral of Applied Mathematics, 2025  DOI

    Tyler Cassidy, Giulia Belluccini, Sarafa A. Iyaniwura, Ruy M. Ribeiro, and Alan S. Perelson

  9. Understanding Cholera Dynamics in African Countries with Persistent Outbreaks: A Mathematical Modelling Approach Preprint

    BMC Public Health (2025) 25:3395  DOI

    Adeniyi Ebenezer, Sarafa A. Iyaniwura, Andrew Omame, Qing Han, Xiaoying Wang, Nicola L. Bragazzi, Woldegebriel A. Woldegerima, and Jude D. Kong.

  10. Leveraging Mathematical Modelling to Evaluate Malaria Vaccination Roll-out Strategies in Cameroon. Preprint

    Submitted to Nature communications, 2025  DOI

    Ruochen Feng, Qing Han, Sarafa A. Iyaniwura, and Jude D. Kong.

  11. Pre-exposure vaccination in the high-risk population is crucial in controlling mpox resurgence in Canada. Preprint

    BMC Infectious Diseases, 2025  DOI

    Andrew Omame, Sarafa A. Iyaniwura, Adeniyi Ebenezer, Qing Han, Xiaoying Wang, Nicola L. Bragazzi, Jude D. Kong, and Woldegebriel A. Woldegerima.

  12. Oscillatory instabilities in dynamically active signalling compartments coupled via bulk diffusion in a 3-D spherical domain. Preprint

    Physica D: Nonlinear Phenomena 476 (2025) 134645  DOI

    Sarafa A. Iyaniwura and Michael J. Ward.

  13. Dynamics of Mpox in an HIV endemic community: A mathematical modelling approach.

    Mathematical Biosciences and Engineering (MBE), Volume 22, Issue 2: 225-259. 2025  DOI

    Andrew Omame, Sarafa A. Iyaniwura, Qing Han, Adeniyi Ebenezer, Nicola L. Bragazzi, Xiaoying Wang, Woldegebriel A. Woldegerima, and Jude D. Kong.

  14. Understanding early HIV-1 rebound dynamics following antiretroviral therapy interruption: The importance of effector cell expansion Preprint

    PLoS Pathogens 20(7): e1012236, 2024  DOI

    Tin Phan, Jessica M Conway, Nicole Pagane, Jasmine Kreig, Narmada Sambaturu, Sarafa A. Iyaniwura, Jonathan Z Li, Ruy M Ribeiro, Ruian Ke, and Alan S Perelson.

  15. A multiscale model of the action of a capsid assembly modulator for the treatment of chronic hepatitis B Preprint

    PLoS Computational Biology 21(5): e1012322.  DOI

    Sarafa A. Iyaniwura, Tyler Cassidy, Ruy M. Ribeiro, and Alan S. Perelson

  16. The kinetics of SARS-CoV-2 infection based on a human challenge study

    PNAS 2024, Vol. 121, No. 46: 121(46)e2406303121.  DOI

    Sarafa A. Iyaniwura, Ruy M. Ribeiro, Carolin Zitzmann, Tin Phan, Ruian Ke, and Alan S. Perelson

  17. Understanding the impact of HIV on mpox transmission in an MSM population: a mathematical modeling study. Preprint

    Infectious Disease Modelling, 9(2024)1117e1137, 2024.  DOI

    Andrew Omame, Qing Han, Sarafa A. Iyaniwura, Adeniyi Ebenezer, Nicola L. Bragazzi, Xiaoying Wang, Jude D. Kong, and Woldegebriel A. Woldegerima.

  18. Regional variation and epidemiological insights in malaria underestimation in Cameroon. Preprint

    Infectious Disease Modelling, Volume 10, Issue 4, Pages 1103-1115, 2025.  DOI.

    Sarafa A. Iyaniwura, Qing Han, Ghislain Rutayisire, Agnes Adom-Konadu, Ngem Bede Yong, Okwen Patrick Mbah, David Poumo Tchouassi, Kingsley Badu, and Jude D. Kong

  19. Asymptotic analysis and simulation of mean first passage time for active Brownian particles in 1-D. Preprint

    SIAM Journal on Applied Mathematics, 2024. Vol. 84, No. 3, pp 1079-1095  DOI.

    Sarafa A. Iyaniwura and Zhiwei Peng

  20. Quantifying the basic reproductionnumber and underestimated fraction ofMpox cases worldwide at the onset ofthe outbreak. Preprint

    Journal of The Royal Society Interface 21: 20230637, Vol. 21, Issue 216, 2024  DOI.

    Nicola Luigi Bragazzi, Sarafa A. Iyaniwura, Qing Han, Woldegebriel Assefa Woldegerima, and Jude Kong

  21. The determinants of malaria transmission and mortality rates in Africa: A cross-country Analysis.

    Selin Tahir, Nicola Luigi Bragazzi, David P. Tchouassi, Mutala Abdul-Hakim, THOMAS KWAME ADDISON, Kingsley Badu, Andreas Buttenschoen, Pravesh Debba, Qing Han, Sarafa A. Iyaniwura, Bruce Mellado Garcia, Zahra Movahedi Nia, Tsholofelo Nyeleti, Xiaoying Wang, and Jude Kong

  22. Understanding the impact of mobility on COVID-19 spread: a hybrid gravity-metapopulation model of COVID-19 Preprint

    PLOS Computational Biology 19(5):e1011123.  DOI

    Sarafa A. Iyaniwura, Notice Ringa, Prince A. Adu, Sunny Mak, Naveed Z. Janjua, Mike A. Irvine, and Michael Otterstatter

  23. A generalized distributed delay model of COVID-19: an endemic model with immunity waning Preprint

    Mathematical Biosciences and Engineering, Volume 20, Issue 3: 5379-5412, 2023.  DOI

    Sarafa Adewale Iyaniwura, Rabiu Musa and Jude D. Kong

  24. Adaptive changes in sexual behavior in the high-risk population in response to human monkeypox transmission in Canada can control the outbreak: insights from a two-group, two-route epidemic model Preprint

    Journal of Medical Virology: 2023;95:e28575.  DOI

    Nicola Luigi Bragazzi, Qing Han, Sarafa Adewale Iyaniwura, Andrew Omame, Aminath Shausan, Xiaoying Wang, Woldegebriel Assefa Woldegerima, Jianhong Wu, and Jude Dzevela Kong

  25. Knowing the unknown: the underestimation of monkeypox cases. Insights and implications from an integrative review of the literature Preprint

    Frontiers in Microbiology: Infectious Agents and Disease. 13:1011049, 2022.  DOI

    Nicola Luigi Bragazzi, Woldegebriel Assefa Woldegerima, Sarafa Adewale Iyaniwura, Qing Han, Xiaoying Wang, Aminath Shausan, Kingsley Badu, Patrick Okwen, Cheryl Prescod, Michelle Westin, Andrew Omame, Manlio Converti, Bruce Mellado, Jianhong Wu and Jude Dzevela Kong

  26. Association between close interpersonal contact and vaccine hesitancy: findings from a population-based survey in Canada Preprint

    Frontiers in Public Health, 2022.  DOI

    Prince A. Adu, Sarafa A. Iyaniwura, Bushra Mahmood, Dahn Jeong, Makuza Jean Damascene, Georgine Cua, Mawuena Binka, Hector A. Velasquez, Notice Ringa, Stanley Wong, Amanda Yu, Mike A. Irvine, Michael Otterstatter, and Naveed Z. Janjua.

  27. The basic reproduction number of COVID-19 across Africa Preprint

    PLoS ONE 17(2), 2022.  DOI

    Sarafa A. Iyaniwura, Rabiu Musa, Jummy F. David, and Jude D. Kong.

  28. Impact of routine asymptomatic screening on COVID-19 incidence in a highly vaccinated university population Preprint

    Submitted to CMAJ Open, 2021. Under review.

    Rebeca Cardim Falcao, Michael Otterstatter, May A. Ahmed, Michelle Spencer, Sarafa A. Iyaniwura, Naveed Z. Janjua, Geoff McKee and Mike A. Irvine

  29. Mathematical modeling of COVID-19 in British Columbia: an age-structured model with time-dependent contact rates Preprint

    Epidemics 39 (2022) 100559.  DOI

    Sarafa A. Iyaniwura, Rebeca Cardim Falcao, Notice Ringa, Prince A. Adu, Michelle Spencer, Marsha Taylor, Caroline Colijn, Daniel Coombs, Naveed Z. Janjua, Mike A. Irvine and Michael Otterstatter

  30. Effect of human mobility on the spatial spread of airborne diseases: an epidemic model with indirect transmission Preprint

    Bulletin of Mathematical Biology (2022) 84:63.  DOI

    Jummy F. David and Sarafa A. Iyaniwura

  31. Social contacts and transmission of COVID-19 in British Columbia, Canada Preprint

    Frontiers in Public Health, 2022  DOI

    Notice Ringa, Sarafa A. Iyaniwura, Samara David, Mike A. Irvine, Prince Adu, Michelle Spencer, Naveed Z. Janjua, and Michael C. Otterstatter

  32. Assessing the potential impact of immunity waning on the dynamics of COVID-19: an endemic model of COVID-19 Preprint

    Nonlinear Dynamics, 2022.  DOI

    Rabiu Musa and Sarafa A. Iyaniwura

  33. Cohort profile: the British Columbia COVID-19 Population Mixing Patterns Survey(BC-Mix) Preprint

    British Medical Journal (BMJ) Open, 2022; 12:e056615.  DOI

    Prince A. Adu, Mawuena Binka, Bushra Mahmood, Dahn Jeong, Terri Buller-Taylor, Makuza Jean Damascene, Sarafa A. Iyaniwura, Notice Ringa, Hector A. Velasquez Garcia, Stanley Wong, Amanda Yu, Sofia Bartlett, James Wilton, Mike A. Irvine, Michael Otterstatter, Naveed Z. Janjua

  34. Assessing the impact of adherence to Non-pharmaceutical interventions and indirect transmission on the dynamics of COVID-19: a mathematical modelling study Preprint

    Mathematical Biosciences and Engineering, 2021 18(6): 8905-8932.  DOI

    Sarafa A. Iyaniwura, Rabiu Musa, Jummy F. David, and Jude D. Kong.

  35. Modeling the potential impact of indirect transmission on COVID-19 epidemic. Preprint

    Submitted to Mathematical Biosciences, 2020: Under review.

    Jummy David, Sarafa A. Iyaniwura, Pei Yuan, Yi Tan, Jude Kong, and Huaiping Zhu.

  36. Quantifying transmissibility of COVID-19 and impact of intervention within long-term health care facilities. Preprint

    Royal Society Open Science. Volume 9 Issue 1, 9: 211710, 2022  DOI

    Jessica E. Stockdale, Sean C. Anderson, Andrew M. Edwards, Sarafa A. Iyaniwura, Nicola Mulberry, Michael C. Otterstatter, Naveed Z. Janjua, Daniel Coombs, Caroline Colijn, and Michael A Irvine.

  37. Importance of COVID-19 vaccine efficacy in older age groups. Preprint

    Vaccine, 2021: Volume 39, Issue 15, Pages 2020-2023.  DOI

    Manish Sadarangani, Bahaa Abu Raya, Jessica M.Conway, Sarafa A. Iyaniwura, Rebeca Cardim Falcao, Caroline Colijn, Daniel Coombs, and Soren Gantt.

  38. Asymptotics of the Principal Eigenvalue of the Laplacian in 2-D Periodic Domains with Small Traps. Preprint

    European J. Applied Math, 2021  DOI

    Frederic Paquin-Lefebvre, Sarafa A. Iyaniwura and Michael J. Ward.

  39. Synchronous Oscillations for a Coupled Cell-Bulk PDE-ODE model with Localized Cells on R^2. Preprint

    Journal of Engr. Math, Vol. 127, No. 18, 2021.  DOI

    Sarafa A. Iyaniwura, Jia Guo and Michael J. Ward.

  40. Pattern Forming Systems Coupling Linear Bulk Diffusion to Dynamically Active Membranes or Cells: Modeling, Analysis, and Computation. Preprint

    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 379(2213), 2021.  DOI

    Daniel Gomez, Sarafa A. Iyaniwura, Frederic Paquin-Lefebvre and Michael J. Ward.

  41. Asymptotic Analysis for the Mean First Passage Time in Finite or Spatially Periodic2-D Domains with a Cluster of Small Traps. Preprint

    The ANZIAM Journal, Volume 63, Issue 1, January 2021, pp. 1-22.  DOI

    Sarafa A. Iyaniwura and Michael J. Ward.

  42. Synchrony and Oscillatory Dynamics for a 2-D PDE-ODE Model of Diffusion-Mediated Communication Between Small Signaling Compartments Preprint

    SIAM J. Applied Dynamical Systems (SIADS), 20(1), 438-499 (62 pages), 2021.  DOI

    Sarafa A. Iyaniwura and Michael J. Ward.

  43. How much leeway is there to relax COVID-19 control measures? Preprint

    Epidemics 35 (2021) 100453.  DOI

    S.C. Anderson, N. Mulberry, A.M. Edwards, J.E. Stockdale, S.A. Iyaniwura, R.C. Falcao, M.C. Otterstatter, N.Z. Janjua, D. Coombs, and C. Colijn.

  44. Localized Signaling Compartments in 2-D Coupled by a Bulk Diffusion Field: Quorum Sensing and Synchronous Oscillations in the Well-Mixed Limit Preprint

    European J. Applied Math, 2020.  DOI

    Sarafa A. Iyaniwura and Michael J. Ward.

  45. Quantifying the impact of COVID-19 control measures using a Bayesian model of physical distancing Preprint

    PLoS computational biology, Vol. 12, No. 16, pages e1008274, 2020.  DOI

    S.C. Anderson, A.M. Edwards, M. Yerlanov, N. Mulberry, J.E. Stockdale, S.A. Iyaniwura, R.C. Falcao, M.C. Otterstatter, M.A. Irvine, N.Z. Janjua, D. Coombs, and C. Colijn.

  46. Optimization of the Mean First Passage Time in Near-Disk and Elliptical Domains in 2-D with Small Absorbing Traps Preprint

    SIAM Review, 2021, Vol. 63, No. 3 : pp. 525-555 .  DOI

    Sarafa A. Iyaniwura, Tony Wong, Colin B. Macdonald and Michael J. Ward.

  47. A novel approach to modelling the spatial spread of airborne diseases: an epidemic model with indirect transmission. Preprint

    Journal of Mathematical Biosciences and Engineering (MBE), 17(4): 3294-3328, 2020.  DOI

    Jummy F. David, Sarafa A. Iyaniwura, Michael J. Ward, and Fred Brauer.

  48. Simulation and Optimization of Mean First Passage Time problem in 2-D using Numerical Embedded methods and perturbation Theory. Preprint

    SIAM J. Multiscale Modeling and Simulation, 2021, Vol. 19, No. 3 : pp. 1367-1393.  DOI

    Sarafa A. Iyaniwura, Tony Wong, Michael J. Ward, and Colin B. Macdonald.

Some Talks and Posters

Theses