A compartmental model of variant coexistence, dynamics and dominance in infectious diseases: Case for SARS-CoV-2 in Abu Dhabi

In recent years, the rapid mutation of SARS-CoV-2 has led to the emergence of new variants. Despite advancements in pandemic control, these new variants could pose substantial public health issues. This study introduces a comprehensive compartmental model that can handle multiple virus variants and population groups. The model also factors the influence of international visitors, per variant and group, on the population, which is pertinent for populations with a high ratio of incoming travellers. The model was applied to simulate the coexistence of different variants in the Emirate of Abu Dhabi from August 2022 until March 2023. Calibration was conducted using the data available from Abu Dhabi health authorities and international data from GISAID to estimate the prevalence of each variant. The model seems to effectively depict the temporal coexistence of multiple strains and, ultimately, the rise of a dominant variant. The simulation results from Abu Dhabi indicate that the XBB variant became the dominant strain by the end of the simulation period. The calibrated parameters for the XBB variant suggest that its dominance can be attributed to its superior ability to evade immunity and its increased infectiousness, estimated to be approximately 15 % more than the BQ.1 variant. The introduction of the XBB variant through infected visitors further amplified its emergence.