Vaccines and variants: Modelling insights into emerging issues in COVID-19 epidemiology

Caldwell, Jamie M.; Le, Xuan Thanh Thi; McIntosh, Lorin; Meehan, Michael T.; Ogunlade, Samson; Ragonnet, Romain; O'Neill, Genevieve K.; Trauer, James M.; McBryde, Emma S.

doi:10.1016/j.prrv.2021.07.002

Cited by 28 publications

(26 citation statements)

References 53 publications

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“…is a new and rapidly evolving disease, other extensions include adapting the SEIR-e model to account for different variants of SARS-CoV-2 [46], the possibility of mutation [47], and the effect of vaccination [48,49] on transmission.…”

Section: Discussionmentioning

confidence: 99%

“…Further extensions of the SEIR-e model include using additional compartments to distinguish between individuals at different stages of infection, or between those who are symptomatic and asymptomatic [3, 18]. As COVID-19 is a new and rapidly evolving disease, other extensions include adapting the SEIR-e model to account for different variants of SARS-CoV-2 [46], the possibility of mutation [47], and the effect of vaccination [48, 49] on transmission.…”

Section: Discussionmentioning

confidence: 99%

“…such that s, e, i, r, u i , v i and τ are non-dimensional. Substituting Eq (46) into Eqs ( 26)- (31) gives the non-dimensional model:…”

Section: Covid-19 Case Study C1 Time Dependent Decay Ratesmentioning

confidence: 99%

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A novel SEIR-e model for disease transmission and pathogen exposure

Tambyah

Testolin

Hill

2022

Preprint

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In this study, we couple compartment models for indoor air quality and disease transmission to develop a novel SEIR-e model for disease transmission and pathogen exposure. In doing so, we gain insight into the contribution of people-people and people-pathogen interactions to the spread of transmissible diseases. A general modelling framework is used to assess the risk of infection in indoor environments due to people-pathogen interactions via inhalation of viral airborne aerosols, and contact with contaminated surfaces. We couple the indoor environment model with a standard disease transmission model to investigate how both people-people and people-pathogen interactions result in disease transmission. The coupled model is referred to as the SEIR-e model. To demonstrate the applicability of the SEIR-e model and the novel insights it can provide into different exposure pathways, parameter values which describe exposure due to people-people and people-pathogen interactions are inferred using Bayesian techniques and case data relating to the 2020 outbreak of COVID-19 in Victoria (Australia).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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A novel SEIR-e model for disease transmission and pathogen exposure

Tambyah

Testolin

Hill

2022

Preprint

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“…Vaccine hesitancy, which is the act of refusal or delay in vaccination, may lead to the accumulation of susceptible individuals, whether as unvaccinated individuals, incomplete vaccination schedules, or natural loss of acquired immunity, which allied to the maintenance of viral circulation, including VOCs of greater transmissibility, such as the Delta variant, may cause new epidemic waves that, with the increase in morbidity and mortality from COVID-19, could jeopardize the population's trust in vaccines and in vaccination as a whole. (23,24) In the study conducted by Yi-Tui Chen (2021), the effect of COVID-19 vaccination was evaluated in eight countries that had reached, by May 2nd, 2021, at least 50% of their population vaccinated (Israel, United Arab Emirates, Chile, United Kingdom, United States of America [USA], Hungary, Qatar, and Serbia), in addition, he estimated the vaccination coverage needed to reach an in exion point in the disease trend. In six of these countries (except the USA and the UK), a peak of cases was also observed after the start of vaccination and before obtaining mass immunity.…”

Section: Discussionmentioning

confidence: 99%

Indirect Impact of COVID-19 Vaccination on Weekly Trends in Morbidity and Mortality Indicators in Brazil, 2020 to 2021

Pércio

Cabral

Fantinato³

et al. 2021

Preprint

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Background: With the outbreak of the COVID-19 pandemic, safe and efficacious vaccines were quickly developed and made available to reduce its morbidity and mortality. This study aimed to describe the trends and evaluate the association of COVID-19 vaccination with indicators of morbidity and mortality due to the disease in Brazil.Methods: This was an ecological study whose unit of analysis was the time elapsed between February 16th, 2020, from the introduction of COVID-19 in Brazil and July 17th, 2021, six months after the start of vaccination in the country. From secondary databases, indicators of morbidity and mortality (incidence of hospitalization, proportion of severe cases, lethality and mortality) and vaccine coverage (doses 1, 2 or single dose) per epidemiological week (EW) and age groups were calculated (18 to 59 years and 60 years or older). Indicators of morbimortality were compared in the pre-vaccination (EW 8/2020 to EW 2/2021) and vaccination (EW 3/2021 to EW 28/2021) periods, analyzing the trends estimated using the JointPoint model and their associations using the Poisson model.Results: For individuals aged 60 years and over, during the period of COVID-19 vaccination there was a weekly trend towards a reduction in the incidence of hospitalizations (PMSV: -4.7%), severity (PMSV: -0.3%, lethality (PMSV: -2.0%) and mortality (PMSV: -2.8%); the increase in COVID-19 vaccination coverage was inversely associated with the incidence of hospitalizations (IRR: 0.969), lethality (IRR: 0.993), and mortality (IRR: 0.981). For individuals aged 18 to 59 years of age, during the period of COVID-19 vaccination there was a weekly trend towards a reduction in the incidence of hospitalizations (PMSV: -2.6%) and lethality (PMSV: -2.0%), while there was an increase in mortality (PMSV: 3.8%); the increase in COVID-19 vaccination coverage was inversely associated with the incidence of hospitalizations (IRR: 0.975) and lethality (IRR: 0.939). Conversely, it was directly associated with mortality (IRR: 1.054).Conclusions: it was demonstrated that COVID-19 vaccination had an indirect impact in reducing the morbidity and mortality trend from the disease in Brazil, especially in the elderly population, in which vaccination was prioritized and achieved greater coverage, when compared to individuals aged 18 to 59 years.

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“…Under this context, the development of new models is providing health authorities and decision-makers around the world an evidence-based tool to inform, guide, update and adapt public health interventions to their unique circumstances and available resources. These models can be used as a tool to forecast potential transmission scenarios and the associated healthcare demand under different vaccination scenarios 22 – 29 and circulating variants 30 , 31 .…”

Section: Introductionmentioning

confidence: 99%

Projecting the impact of Covid-19 variants and vaccination strategies in disease transmission using a multilayer network model in Costa Rica

García

Mery²,

Vásquez

et al. 2022

Sci Rep

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For countries starting to receive steady supplies of vaccines against SARS-CoV-2, the course of Covid-19 for the following months will be determined by the emergence of new variants and successful roll-out of vaccination campaigns. To anticipate this scenario, we used a multilayer network model developed to forecast the transmission dynamics of Covid-19 in Costa Rica, and to estimate the impact of the introduction of the Delta variant in the country, under two plausible vaccination scenarios, one sustaining Costa Rica’s July 2021 vaccination pace of 30,000 doses per day and with high acceptance from the population and another with declining vaccination pace to 13,000 doses per day and with lower acceptance. Results suggest that the introduction and gradual dominance of the Delta variant would increase Covid-19 hospitalizations and ICU admissions by $$35\%$$ 35 % and $$33.25\%$$ 33.25 % , respectively, from August 2021 to December 2021, depending on vaccine administration and acceptance. In the presence of the Delta variant, new Covid-19 hospitalizations and ICU admissions are estimated to increase around $$24.26\%$$ 24.26 % and $$27.19\%$$ 27.19 % , respectively, in the same period if the vaccination pace drops. Our results can help decision-makers better prepare for the Covid-19 pandemic in the months to come.

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Vaccines and variants: Modelling insights into emerging issues in COVID-19 epidemiology

Cited by 28 publications

References 53 publications

A novel SEIR-e model for disease transmission and pathogen exposure

A novel SEIR-e model for disease transmission and pathogen exposure

Indirect Impact of COVID-19 Vaccination on Weekly Trends in Morbidity and Mortality Indicators in Brazil, 2020 to 2021

Projecting the impact of Covid-19 variants and vaccination strategies in disease transmission using a multilayer network model in Costa Rica

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