Modelling the interplay of SARS-CoV-2 variants in the United Kingdom

Abstract

Many COVID-19 vaccines are proving to be highly effective to prevent severe disease and to diminish infections. Their uneven geographical distribution favors the appearance of new variants of concern, as the highly transmissible Delta variant, affecting particularly non-vaccinated people. It is important to device reliable models to analyze the spread of the different variants. A key factor is to consider the effects of vaccination as well as other measures used to contain the pandemic like social behaviour. The stochastic geographical model presented here, fulfills these requirements. It is based on an extended compartmental model that includes various strains and vaccination strategies, allowing to study the emergence and dynamics of the new COVID-19 variants. The model conveniently separates the parameters related to the disease from the ones related to social behavior and mobility restrictions. We applied the model to the United Kingdom by using available data to fit the recurrence of the currently prevalent variants. Our computer simulations allow to describe the appearance of periodic waves and the features that determine the prevalence of certain variants. They also provide useful predictions to help planning future vaccination boosters. We stress that the model could be applied to any other country of interest.

Socio-economic pandemic modelling: Case of Spain

“…In this study we aim to model the COVID-19 pandemic and its socio-economic effects in Spain using the hybrid BTH-SEIRS model presented in 13 . This is the first time that the model is applied to a realistic situation, and as such we have made some necessary modifications as well as some additions suggested by our other recent works 6,8 , such as implementations of vaccinations and virus strains. The structure of the model is illustrated in Fig.…”

“…The BTH-SEIRS model has both epidemiological and social parameters. The former parameters were set according to our former publication 8 , taking into account the virulence of different virus variants and the rate of population immunization. This work seeks to understand the social and economic dynamics of the population in response to the pandemic, therefore we do not attempt to replicate the curves of the number of cases.…”

“…As stated above, we treated the SEIRS parameters (λ , ε, etc) as constants that have already been determined by previous works on the pure SEIRS model (see, e.g. 5,6,8 ), while we treated the value parameters governing the activities of the agents as adjustable. Our goal was then to find the numerical values of the value parameters that produced better match the real world data.…”

“…), upo which we could do data-driven modeling, as there is trustworthy quantification of the number of contagions and deaths caused by Covid-19. There are various models that have recently been developed to deal with the dynamical spread of the disease over a geographical region, (see for instance [3][4][5][6][7][8] ), and also studies about the behaviour of several economic indexes during hazardous times 9 . However, only a few studies take into account both, the economic performance and the spread of the pandemic simultaneously, which is the problem we focus on here.…”

Pathways to discontinuous transitions in interacting contagion dynamics

“…Alternatively, the presence of one pathogen in the population might hamper the propagation of another one. Such competition is usually observed in the epidemic trajectories of viruses with multiple strains circulating simultaneously, such as influenza [12] and DENV [13] or more recently in the complex landscape depicted by the different SARS-CoV-2 variants [14,15]. Outside the domain of interacting epidemics, another clear example of the relevance of interdependencies among simultaneous dynamics is the influence of social behavior on epidemic spreading [16,17].…”