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Angelov G, Kovacevic R, Stilianakis NI, Veliov VM. An immuno-epidemiological model with waning immunity after infection or vaccination. J Math Biol 2024; 88:71. [PMID: 38668894 PMCID: PMC11052727 DOI: 10.1007/s00285-024-02090-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 02/19/2024] [Accepted: 03/31/2024] [Indexed: 04/29/2024]
Abstract
In epidemics, waning immunity is common after infection or vaccination of individuals. Immunity levels are highly heterogeneous and dynamic. This work presents an immuno-epidemiological model that captures the fundamental dynamic features of immunity acquisition and wane after infection or vaccination and analyzes mathematically its dynamical properties. The model consists of a system of first order partial differential equations, involving nonlinear integral terms and different transfer velocities. Structurally, the equation may be interpreted as a Fokker-Planck equation for a piecewise deterministic process. However, unlike the usual models, our equation involves nonlocal effects, representing the infectivity of the whole environment. This, together with the presence of different transfer velocities, makes the proved existence of a solution novel and nontrivial. In addition, the asymptotic behavior of the model is analyzed based on the obtained qualitative properties of the solution. An optimal control problem with objective function including the total number of deaths and costs of vaccination is explored. Numerical results describe the dynamic relationship between contact rates and optimal solutions. The approach can contribute to the understanding of the dynamics of immune responses at population level and may guide public health policies.
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Affiliation(s)
- Georgi Angelov
- Institute of Statistics and Mathematical Methods in Economics, Vienna University of Technology, Vienna, Austria
| | - Raimund Kovacevic
- Department for Economy and Health, University for Continuing Education Krems, Krems an der Donau, Austria
| | - Nikolaos I Stilianakis
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
- Department of Biometry and Epidemiology, University of Erlangen-Nuremberg, Erlangen, Germany.
| | - Vladimir M Veliov
- Institute of Statistics and Mathematical Methods in Economics, Vienna University of Technology, Vienna, Austria
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Idisi OI, Yusuf TT, Owolabi KM, Ojokoh BA. A bifurcation analysis and model of Covid-19 transmission dynamics with post-vaccination infection impact. HEALTHCARE ANALYTICS (NEW YORK, N.Y.) 2023; 3:100157. [PMID: 36941830 PMCID: PMC10007718 DOI: 10.1016/j.health.2023.100157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/01/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023]
Abstract
SARS COV-2 (Covid-19) has imposed a monumental socio-economic burden worldwide, and its impact still lingers. We propose a deterministic model to describe the transmission dynamics of Covid-19, emphasizing the effects of vaccination on the prevailing epidemic. The proposed model incorporates current information on Covid-19, such as reinfection, waning of immunity derived from the vaccine, and infectiousness of the pre-symptomatic individuals into the disease dynamics. Moreover, the model analysis reveals that it exhibits the phenomenon of backward bifurcation, thus suggesting that driving the model reproduction number below unity may not suffice to drive the epidemic toward extinction. The model is fitted to real-life data to estimate values for some of the unknown parameters. In addition, the model epidemic threshold and equilibria are determined while the criteria for the stability of each equilibrium solution are established using the Metzler approach. A sensitivity analysis of the model is performed based on the Latin Hypercube Sampling (LHS) and Partial Rank Correlation Coefficients (PRCCs) approaches to illustrate the impact of the various model parameters and explore the dependency of control reproduction number on its constituents parameters, which invariably gives insight on what needs to be done to contain the pandemic effectively. The foregoing notwithstanding, the contour plots of the control reproduction number concerning some of the salient parameters indicate that increasing vaccination coverage and decreasing vaccine waning rate would remarkably reduce the value of the reproduction number below unity, thus facilitating the possible elimination of the disease from the population. Finally, the model is solved numerically and simulated for different scenarios of disease outbreaks with the findings discussed.
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Affiliation(s)
- Oke I Idisi
- Department of Mathematical Sciences, Federal University of Technology, Akure, P.M.B. 704, Ondo State, Nigeria
| | - Tunde T Yusuf
- Department of Mathematical Sciences, Federal University of Technology, Akure, P.M.B. 704, Ondo State, Nigeria
| | - Kolade M Owolabi
- Department of Mathematical Sciences, Federal University of Technology, Akure, P.M.B. 704, Ondo State, Nigeria
| | - Bolanle A Ojokoh
- Department of Information Systems, Federal University of Technology, Akure, P.M.B. 704, Ondo State, Nigeria
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Pazos-Guerra M, Ruiz-Sánchez JG, Pérez-Candel X, López-Nevado C, Hernández-Olmeda F, Cuesta-Hernández M, Martín-Sánchez J, Calle-Pascual AL, Runkle-de la Vega I. Inappropriate therapy of euvolemic hyponatremia, the most frequent type of hyponatremia in SARS-CoV-2 infection, is associated with increased mortality in COVID-19 patients. Front Endocrinol (Lausanne) 2023; 14:1227059. [PMID: 37560297 PMCID: PMC10408442 DOI: 10.3389/fendo.2023.1227059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 06/30/2023] [Indexed: 08/11/2023] Open
Abstract
Introduction Admission hyponatremia, frequent in patients hospitalized for COVID-19, has been associated with increased mortality. However, although euvolemic hyponatremia secondary to the Syndrome of Inappropriate Antidiuresis (SIAD) is the single most common cause of hyponatremia in community-acquired pneumonia (CAP), a thorough and rigorous assessment of the volemia of hyponatremic COVID-19 subjects has yet to be described. We sought to identify factors contributing to mortality and hospital length-of-stay (LOS) in hospitalized COVID-19 patients admitted with hyponatremia, taking volemia into account. Method Retrospective study of 247 patients admitted with COVID-19 to a tertiary hospital in Madrid, Spain from March 1st through March 30th, 2020, with a glycemia-corrected serum sodium level (SNa) < 135 mmol/L. Variables were collected at admission, at 2nd-3rd day of hospitalization, and ensuing days when hyponatremia persisted. Admission volemia (based on both physical and analytical parameters), therapy, and its adequacy as a function of volemia, were determined. Results Age: 68 years [56-81]; 39.9% were female. Median admission SNa was 133 mmol/L [131- 134]. Hyponatremia was mild (SNa 131-134 mmol/L) in 188/247 (76%). Volemia was available in 208/247 patients; 57.2% were euvolemic and the rest (42.8%) hypovolemic. Hyponatremia was left untreated in 154/247 (62.3%) patients. Admission therapy was not concordant with volemia in 43/84 (51.2%). In fact, the majority of treated euvolemic patients received incorrect therapy with isotonic saline (37/41, 90.2%), whereas hypovolemics did not (p=0.001). The latter showed higher mortality rates than those receiving adequate or no therapy (36.7% vs. 19% respectively, p=0.023). The administration of isotonic saline to euvolemic hyponatremic subjects was independently associated with an elevation of in-hospital mortality (Odds Ratio: 3.877, 95%; Confidence Interval: 1.25-12.03). Conclusion Hyponatremia in COVID-19 is predominantly euvolemic. Isotonic saline infusion therapy in euvolemic hyponatremic COVID-19 patients can lead to an increased mortality rate. Thus, an exhaustive and precise volemic assessment of the hyponatremic patient with CAP, particularly when due to COVID-19, is mandatory before instauration of therapy, even when hyponatremia is mild.
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Affiliation(s)
- Mario Pazos-Guerra
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Jorge Gabriel Ruiz-Sánchez
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria Fundación Jiménez-Díaz (IIS-FJD), Universidad Autónoma de Madrid (UAM), Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain
| | - Xavier Pérez-Candel
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Celia López-Nevado
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Fernando Hernández-Olmeda
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Martin Cuesta-Hernández
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Javier Martín-Sánchez
- Medicine II Department, Universidad Complutense de Madrid, Madrid, Spain
- Emergency Department, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Emergency Department, Hospital Clínico San Carlos, Madrid, Spain
| | - Alfonso Luis Calle-Pascual
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Medicine II Department, Universidad Complutense de Madrid, Madrid, Spain
| | - Isabelle Runkle-de la Vega
- Department of Endocrinology and Nutrition, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
- Medicine II Department, Universidad Complutense de Madrid, Madrid, Spain
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