Transient dynamics – SARS-CoV-2 viral rebounds with and without treatments (monoclonal antibody/antiviral therapy)

In the vast majority of cases, the characteristics of SARS-CoV-2 viral dynamics follow that of an acute infection, with viral load rapidly peaking around 5 days post-infection and clearing up within 2 weeks. Interestingly, some individuals show signs of viral recrudescence of up to 10000 viral RNA copies/mL shortly following viral remission. In these cases, the viral rebound is often cleared up within 4 weeks (post-infection), differentiating it from long COVID. These cases of viral rebounds have been observed in untreated, treated (with either monoclonal antibody or antiviral drug), vaccinated, unvaccinated, and infections with different viral strains. In this talk, I will first review the evidence of transient viral rebound. Then, I will show that a class of dynamic models that incorporates virus-immune interaction accurately describes transient viral rebound dynamics under different treatment scenarios (including untreated). While these models all share a simple structure with a unique globally-asymptomatic-stable disease-free equilibrium without bifurcation, the most exciting and relevant aspect hides within their transient phase and remains largely unexplored.