Mathematical Modeling and Robustness Analysis to Unravel COVID-19 Transmission Dynamics: The Italy Case

Antonini, Chiara; Calandrini, Sara; Stracci, Fabrizio; Dario, Claudio; Bianconi, Fortunato

doi:10.3390/biology9110394

Cited by 5 publications

(11 citation statements)

References 25 publications

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“…In this study, we use and extend the SEIRL model presented in [ 19 ], with the introduction of vaccinations (SEIRL-V). The SEIRL-V compartmental model is shown in Figure 1 and it includes twelve infection states.…”

Section: Methodsmentioning

confidence: 99%

“…All infected classes can instead recover and evolve to the R class. Here, differently from the authors of [ 19 ], we suppose that both people in H and

class can die. Susceptible individuals are vaccinated with the injection of two doses (classes

and

).…”

Section: Methodsmentioning

confidence: 99%

“…In order to introduce this hypothesis, the transmission rate parameters of presymtpomatic and asymptomatic infected are given by

where

is the time of introduction of the new variants. Using the next generation matrix, the formula for computing the basic reproduction number

, i.e., the number of individuals infected by a single infected individual during his infectious period, is [ 4 , 19 , 31 ]:

…”

Section: Methodsmentioning

confidence: 99%

“…CRC is an iterative algorithm for parameter estimation, belonging to the class of Approximate Bayesian Computation Sequential Monte Carlo (ABC-SMC) methodologies. A detailed description of CRC can be found in [ 19 , 20 , 21 , 22 ]. CRC is based on the sampling of the parameter space and it considers the parameter vector as a random variable P .…”

Section: Methodsmentioning

confidence: 99%

“…Here, we extend the SEIR model with intervention parameters (SEIRL) presented in [ 19 ] to include the presence of new variants and vaccination roll-out (SEIRL-V). We focus on the case study of Italy and of the Umbria region, the first region displaying the emergence of variants.…”

Section: Introductionmentioning

confidence: 99%

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A Modeling Study on Vaccination and Spread of SARS-CoV-2 Variants in Italy

Antonini¹,

Calandrini

Bianconi³

2021

Vaccines

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From the end of 2020, different vaccines against COVID-19 have been approved, offering a glimmer of hope and relief worldwide. However, in late 2020, new cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started to re-surge, worsened by the emergence of highly infectious variants. To study this scenario, we extend the Susceptible-Exposed-Infectious-Removed model with lockdown measures used in our previous work with the inclusion of new lineages and mass vaccination campaign. We estimate model parameters using the Bayesian method Conditional Robust Calibration in two case studies: Italy and the Umbria region, the Italian region being worse affected by the emergence of variants. We then use the model to explore the dynamics of COVID-19, given different vaccination paces and a policy of gradual reopening. Our findings confirm the higher reproduction number of Umbria and the increase of transmission parameters due to the presence of new variants. The results illustrate the importance of preserving population-wide interventions, especially during the beginning of vaccination. Finally, under the hypothesis of waning immunity, the predictions show that a seasonal vaccination with a constant rate would probably be necessary to control the epidemic.

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Section: Methodsmentioning

confidence: 99%

“…All infected classes can instead recover and evolve to the R class. Here, differently from the authors of [ 19 ], we suppose that both people in H and

class can die. Susceptible individuals are vaccinated with the injection of two doses (classes

and

).…”

Section: Methodsmentioning

confidence: 99%

“…In order to introduce this hypothesis, the transmission rate parameters of presymtpomatic and asymptomatic infected are given by

where

is the time of introduction of the new variants. Using the next generation matrix, the formula for computing the basic reproduction number

, i.e., the number of individuals infected by a single infected individual during his infectious period, is [ 4 , 19 , 31 ]:

…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Modeling Study on Vaccination and Spread of SARS-CoV-2 Variants in Italy

Antonini¹,

Calandrini

Bianconi³

2021

Vaccines

Self Cite

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Impact of Nonpharmaceutical Interventions on ICU Admissions During Lockdown for Coronavirus Disease 2019 in New Zealand—A Retrospective Cohort Study

Gonzenbach

McGuinness

Parke³

et al. 2021

Critical Care Medicine

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OBJECTIVES: Nonpharmaceutical interventions are implemented internationally to mitigate the spread of severe acute respiratory syndrome coronavirus 2 with the aim to reduce coronavirus disease 2019–related deaths and to protect the health system, particularly intensive care facilities from being overwhelmed. The aim of this study is to describe the impact of nonpharmaceutical interventions on ICU admissions of non–coronavirus disease 2019–related patients. DESIGN: Retrospective cohort study. SETTING: Analysis of all reported adult patient admissions to New Zealand ICUs during Level 3 and Level 4 lockdown restrictions from March 23, to May 13, 2020, in comparison with equivalent periods from 5 previous years (2015–2019). SUBJECTS: Twelve-thousand one-hundred ninety-two ICU admissions during the time periods of interest were identified. MEASUREMENTS: Patient data were obtained from the Australian and New Zealand Intensive Care Society Adult Patient Database, Australian and New Zealand Intensive Care Society critical care resources registry, and Statistics New Zealand. Study variables included patient baseline characteristics and ICU resource use. MAIN RESULTS: Nonpharmaceutical interventions in New Zealand were associated with a 39.1% decrease in ICU admission rates ( p < 0.0001). Both elective (–44.2%) and acute (–36.5%) ICU admissions were significantly reduced when compared with the average of the previous 5 years (both p < 0.0001). ICU occupancy decreased from a mean of 64.3% (2015–2019) to 39.8% in 2020. Case mix, ICU resource use per patient, and ICU and hospital mortality remained unchanged. CONCLUSIONS: The institution of nonpharmaceutical interventions was associated with a significant decrease in elective and acute ICU admissions and ICU resource use. These findings may help hospitals and health authorities planning for surge capacities and elective surgery management in future pandemics.

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Robustness analysis for quantitative assessment of vaccination effects and SARS-CoV-2 lineages in Italy

Antonini¹,

Calandrini

Bianconi³

2022

BMC Infect Dis

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Background In Italy, the beginning of 2021 was characterized by the emergence of new variants of SARS-CoV-2 and by the availability of effective vaccines that contributed to the mitigation of non-pharmaceutical interventions and to the avoidance of hospital collapse. Methods We analyzed the COVID-19 propagation in Italy starting from September 2021 with a Susceptible-Exposed-Infected-Recovered (SEIR) model that takes into account SARS-CoV-2 lineages, intervention measures and efficacious vaccines. The model was calibrated with the Bayesian method Conditional Robust Calibration (CRC) using COVID-19 data from September 2020 to May 2021. Here, we apply the Conditional Robustness Analysis (CRA) algorithm to the calibrated model in order to identify model parameters that most affect the epidemic diffusion in the long-term scenario. We focus our attention on vaccination and intervention parameters, which are the key parameters for long-term solutions for epidemic control. Results Our model successfully describes the presence of new variants and the impact of vaccinations and non-pharmaceutical interventions in the Italian scenario. The CRA analysis reveals that vaccine efficacy and waning immunity play a crucial role for pandemic control, together with asymptomatic transmission. Moreover, even though the presence of variants may impair vaccine effectiveness, virus transmission can be kept low with a constant vaccination rate and low restriction levels. Conclusions In the long term, a policy of booster vaccinations together with contact tracing and testing will be key strategies for the containment of SARS-CoV-2 spread.

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Mathematical Modeling and Robustness Analysis to Unravel COVID-19 Transmission Dynamics: The Italy Case

Cited by 5 publications

References 25 publications

A Modeling Study on Vaccination and Spread of SARS-CoV-2 Variants in Italy

A Modeling Study on Vaccination and Spread of SARS-CoV-2 Variants in Italy

Impact of Nonpharmaceutical Interventions on ICU Admissions During Lockdown for Coronavirus Disease 2019 in New Zealand—A Retrospective Cohort Study

Robustness analysis for quantitative assessment of vaccination effects and SARS-CoV-2 lineages in Italy

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