Current scenario of COVID-19 in pediatric age group and physiology of immune and thymus response

Abstract

COVID-19 pandemic caused by SARS-CoV-2, continues to manifest with severe acute respiratory syndrome among the adults, however, it offers a convincing indication of less severity and fatality in pediatric age group (0-18 years). The current trend suggests that children may get infected but are less symptomatic with less fatality, which is concordant to earlier epidemic outbreaks of SARS-CoV and MERS-CoV, in 2002 and 2012, respectively. According to the available data, children appear to be at lower risk for COVID-19, as adults constitute for maximum number of the confirmed cases (308,592) and deaths (13,069) as on 22nd March (https://www.worldometers.info/coronavirus). However, rapid publications and information of the adult patients with COVID-19 is in progress and published, on the contrary, almost no comprehensive data or discussion about the COVID-19 in children is available. Therefore, in this review, we outline the epidemiology, clinical symptoms, diagnosis, treatment, prevention, possible immune response and role of thymus in children to combat the COVID-19 outbreak.

Keywords: ARDS, Acute Respiratory Distress Syndrome; COVID-19; COVID-19, Coronavirus Disease-2019; Children; Coronaviruses; Immunity; MERS-CoV, Middle East Respiratory Syndrome Coronavirus; Pandemic; SARS-CoV, Severe Acute Respiratory Syndrome Coronavirus; Thymus; WHO, World Health Organization; pp1ab, Polyprotein 1ab.

Fig. 1

Illustration of fatality rate (percentage) among different age group in COVID-19. The sources of data presented is https://www.worldometers.info/coronavirus/https://www.statista.com/statistics/1095024/china-age-distribution-of-wuhan-coronavirus-covid-19-patients/.

Fig. 2

Role of thymus gland in viral infection. Illustration shows CD138⁺ plasma cells (PC) accumulated in thymic perivascular space, where they constitutively produce IgG1 and IgG3 which are reactive to common viral proteins and IgG subclass with no function.