Longitudinal immunological outcomes from three doses of COVID-19 vaccines in people living with HIV: antibodies, memory-B cells, cytokines, and a novel within-host immunological model
Chapin S. Korosec [1,2], Vitaliy Matveev , Mario Ostrowski , Jane M. Heffernan [1,2]
 Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada
 Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada
 Department of Medicine, University of Toronto, Toronto, Ontario, Canada
People living with HIV (PLWH) older than age 55 have an enhanced risk of complications from SARS-CoV-2 infection. It is further unclear whether multiple standard doses of COVID-19 vaccines elicit a durable immunity in this population or whether the vaccines can destabilize HIV reservoirs. In this talk I will discuss our unpublished work where we followed n = 91 PLWH aged 55+ and n = 23 age-matched HIV- individuals over a period of 48 weeks following COVID-19 dose one, capturing longitudinal immunological outcomes from two subsequent booster doses. I will introduce the longitudinal immunological findings for IgG, memory-B cells, and cytokines (IFNg and IL2). I will then motivate our novel within-host immunological model which couples these quantities together, and the findings of our fits to determine dose-dependent decay rates and half life values. Model fit findings, practical identifiability concerns, and biological implications of the within-host modelling approach will be discussed.