Evidence-Based Medicine
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Exp Med. Jun 20, 2023; 13(3): 28-46
Published online Jun 20, 2023. doi: 10.5493/wjem.v13.i3.28
Role of children in the Bulgarian COVID-19 epidemic: A mathematical model study
Latchezar Tomov, Hristiana Batselova, Snezhina Lazova, Borislav Ganev, Iren Tzocheva, Tsvetelina Velikova
Latchezar Tomov, Department of Informatics, New Bulgarian University, Sofia 1618, Bulgaria
Hristiana Batselova, Department of Epidemiology and Disaster Medicine, Medical University, University Hospital "St George", Plovdiv 6000, Bulgaria
Snezhina Lazova, Borislav Ganev, Department of Pediatric, University Hospital "N. I. Pirogov", Sofia 1606, Bulgaria
Snezhina Lazova, Department of Healthcare, Faculty of Public Health, Medical University of Sofia, Sofia 1527, Bulgaria
Iren Tzocheva, Department of Pediatric, Medical Faculty, University Hospital "N. I. Pirogov", Sofia 1606, Bulgaria
Tsvetelina Velikova, Medical Faculty, Sofia University, St. Kliment Ohridski, Sofia 1407, Bulgaria
Author contributions: Tomov L and Velikova T contributed to conceptualization; Tomov L, Lazova S, Batselova H, Ganev B, Tzocheva I, and Velikova T contributed to resources and literature review; Tomov L, Lazova S, Batselova H, Ganev B, and Tzocheva I contributed to writing – original draft preparation; Velikova T, Ganev L contributed to writing – review & editing; Velikova T contributed to supervision; All authors revised and approved the final version of the manuscript.
Supported by the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria Project, No. BG-RRP-2.004-0008-C01.
Conflict-of-interest statement: All the authors declare no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Latchezar Tomov, PhD, Academic Research, Assistant Professor, Department of Informatics, New Bulgarian University, Montevideo 21 Street, Sofia 1618, Bulgaria. luchesart@gmail.com
Received: January 6, 2023
Peer-review started: January 6, 2023
First decision: March 15, 2023
Revised: April 7, 2023
Accepted: May 22, 2023
Article in press: May 22, 2023
Published online: June 20, 2023
Processing time: 160 Days and 17.1 Hours
Abstract
BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic affects all aspects of our lives, including children. With the advancement of the pandemic, children under five years old are at increased risk of hospitalization relative to other age groups. This makes it paramount that we develop tools to address the two critical aspects of preserving children's health – new treatment protocols and new predictive models. For those purposes, we need to understand better the effects of COVID-19 on children, and we need to be able to predict the number of affected children as a proportion of the number of infected children. This is why our research focuses on clinical and epidemiological pictures of children with heart damage post-COVID, as a part of the general picture of post-COVID among this age group.

AIM

To demonstrate the role of children in the COVID-19 spread in Bulgaria and to test the hypothesis that there are no secondary transmissions in schools and from children to adults.

METHODS

Our modeling and data show with high probability that in Bulgaria, with our current measures, vaccination strategy and contact structure, the pandemic is driven by the children and their contacts in school.

RESULTS

This makes it paramount that we develop tools to address the two critical aspects of preserving children's health – new treatment protocols and new predictive models. For those purposes, we need to understand better the effects of COVID-19 on children, and we need to be able to predict the number of affected children as a proportion of the number of infected children. This is why our research focuses on clinical and epidemiological pictures of children with heart damage post-COVID, as a part of the general picture of post-Covid among this age group.

CONCLUSION

Our modeling rejects that hypothesis, and the epidemiological data supports that. We used epidemiological data to support the validity of our modeling. The first summer wave in 2020 from the listed here school proms endorse the idea of transmissions from students to teachers.

Keywords: COVID-19; Pandemic; Children; Cardiac involvement; Multisystem inflammation in children; ARIMA; Time-series modeling; Regression model

Core Tip: The lack of vaccination strategy accelerates the spread of coronavirus disease 2019 among children and accelerate the spread among people below 50 years. Based on the latter hypothesis and the other three: (1) Disease spreads from children to adults – either directly to parents and grandparents or via network spread to different age groups; (2) the spread among children accelerates with the increasing R0 of different dominating viral variants; and (3) vaccinations among adults accelerate the spread among the less vaccinated group of children, we outlined the reasons for this age-restricted acceleration of the spread after the delta wave.