COVID-19 waves: variant dynamics and control

Abstract

The waves of COVID-19 infections driven by its variants continue to nullify the success we achieved through efficacious vaccines, social restrictions, testing and quarantine policies. This paper models the two major variants-driven waves by two sets of susceptible-infected-quarantined-recovered-vaccinated-deceased coupled dynamics that are modulated by the three main interventions: vaccination, quarantine and restrictions. This $$SI^2Q^2R^2VD$$ S I 2 Q 2 R 2 V D system is used to demonstrate that the second major novel coronavirus wave in the US is caused by the delta variant and the corresponding rapid surge in infectious cases is driven by the unvaccinated pool of the populace. Next, a feedback control based planned vaccination strategy is derived and is shown to be able to suppress the surge in infections effectively.

The Impact of Demographic, Clinical Characteristics and the Various COVID-19 Variant Types on All-Cause Mortality: A Case-Series Retrospective Study

“…Our results indicate that the second and third waves were more serious than the other waves. This correlates with the increase in the severity of disease and community transmission that was observed with Alpha and Delta variants, respectively [ 31 , 32 , 33 , 34 ].…”

“…Several studies suggested that the COVID-19 surges appeared as a result of mutations in the SARS-CoV-2 virus and the emergence of new variants that are more virulent and transmissible [35][36][37][38][39]. The occurrence of mutations in the SARS-CoV-2 viral genome during replication is a natural phenomenon that has led to a number of novel variants [34,35].…”

Differentiation of SARS-CoV-2 Variants Using RT-qPCRs by Targeting Recurrent Mutation Sites: A Diagnostic Laboratory Experience from Multi-Center Regional Study, August 2020–December 2021, Poland

“…The vaccination is one of the most effective ways to protect from infectious diseases. The development of vaccines against COVID-19 proved successful in preventing symptomatic infection and illness; however, despite the availability of vaccines, many countries experienced multiple COVID-19 waves, largely caused and driven by emerging new VOCs [ 27 ]; they prolong the continuation of the disease, leading to patient deaths, economic losses and a further burden on public health systems [ 4 ]. Globally, five COVID-19 waves were observed during the study period, from 1 August 2020 to 31 December 2021 [ 3 ].…”

Computational systems biology in disease modeling and control, review and perspectives

“…The main task of parameter estimation is to find the best-fit parameters to characterize physical processes and reproduce experiments 136 – 138 . To develop data-driven models, one can optimize the fit of a collection of parameters iteratively to a given dataset with random disturbance 137 , 139 , which explores the parameter space extensively and limits the number of non-convergent solutions 131 .…”

“…There are some other control strategies that use feedback control laws based on nonlinear models. For example, a positive semi-definite Lyapunov function, whose gradient requires to be negative semi-definite, can be designed to calculate the controlled vaccination rate that asymptotically stabilizes Covid infection 138 .…”