key: cord-0695996-98bzo6qy
authors: Yurttutan, Sadık; İpek, Sevcan; Güllü, Utku U.
title: Why the SARS‐Cov‐2 has prolonged spreading time in children?
date: 2020-05-01
journal: Pediatr Pulmonol
DOI: 10.1002/ppul.24795
sha: 8f15409988c3a534529d02009a5c1e8b61eec91d
doc_id: 695996
cord_uid: 98bzo6qy

nan

Why the SARS-Cov-2 has prolonged spreading time in children?

To the Editor,

We read the article written by Lin et al with interest and would like to share our opinion on it. 1 On the basis of the literature, child patients with SARS-Cov-2, especially those below the age of 15, have shown to experience very mild infections. 2 What are the reasons for these clinical differences between the elderly and young people? The current literature provides no clear explanation.

In the pathogenesis of a standard viral infection, the pathogen's contact with the mucosa is initially followed by an innate immunity response (macrophage, antigen-presenting, and natural killer cell). The objective is to eliminate the pathogen in the initial stage. Subsequently, adaptive immunity comes into play and is responsible for the elimination of infected cells, activation of the antibody response, and production of memory T cells. T cells are the primary, decisive element in adaptive immunity capability. For this reason, the adaptive immune response mediated by the thymus is a process that regulates the immune response responsible for preventing invasive damage from a virus. Thus, the thymus-mediated adaptive immune response plays a vital role against viral infections.

Aging presents structural and functional loss affecting the entire system and precisely, the immune system. 3 In your article, the case of the 7-year-old involves a prolonged respiratory positivity for SARS-Cov-2. However, the article did not include any clarification on the possible causes of this situation.

We believe that this situation can be explained by the differences in the immune response of age groups. Children have a more controlled immune response compared to adults and even though this prevents tissue damage, it also prolongs the full elimination time

The isolation period should be longer: lesson from a child infected with SARS-CoV-2 in Chongqing, China. Pediatr Pulmonol

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Increased regulatory T cells and impaired functions of circulating CD8 T lymphocytes is associated with viral persistence in Hepatitis B virus-positive newborns