Tomov L, Batselova H, Lazova S, Ganev B, Tzocheva I, Velikova T. Role of children in the Bulgarian COVID-19 epidemic: A mathematical model study. World J Exp Med 2023; 13(3): 28-46 [PMID: 37396885 DOI: 10.5493/wjem.v13.i3.28]
Corresponding Author of This Article
Latchezar Tomov, PhD, Academic Research, Assistant Professor, Department of Informatics, New Bulgarian University, Montevideo 21 Street, Sofia 1618, Bulgaria. luchesart@gmail.com
Research Domain of This Article
Statistics & Probability
Article-Type of This Article
Evidence-Based Medicine
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: http://creativecommons.org/licenses/by-nc/4.0/
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 bythe 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
ARTICLE HIGHLIGHTS
Research background
Transmission from children to adults was deemed secondary to the transmission from adults to children. After the first big wave in September to December 2020, masks were mandated in grades 5 and above but not enforced, with arguably low adherence, less than the general adherence due to mask removal in breaks between classes.
Research motivation
With starting the pandemic in Bulgaria, children were mostly speared from infection. On the one hand, it was thought that coronavirus disease 2019 (COVID-19) took a mild course in children. On the other hand, the testing was at the lowest rate among children. Up to now, the total number of infected children (0-18 years) is 103743.
Research objectives
We aimed 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.
Research methods
We used ARIMA models with external regressors and Poisson distribution modeling to test our hypotheses.
Research results
Our models allows to predict the new weekly cases in different age groups from the new cases in children one and two week prior. The age groups 50-59 and 90+ are less predictable and are also more isolated from children, consistent with the idea that children drive the pandemic in Bulgaria.
Research conclusions
Our models support the hypothesis that children are drivers of the pandemic in Bulgaria.
Research perspectives
In the first year of the pandemic it was suggested that children rarely transmit the virus to adults. On this basis Bulgarian Ministry of Health decided to allow the parents of quarantined children to continue to work and move freely in society. We will use more sophisticated models such as branching process to demonstrate that even if the probability of infection from children to adults is very low, the free movement of the parents will still trigger a pandemic wave.
