en ویروس شناسی Virology پژوهشي Research <div style="text-align: justify;">SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) and is responsible for the recent pandemic in the world. It has been recently recognized as a challenge for public health and a significant cause of severe illness in all age groups. Young children and older people are susceptible to SARS-CoV-2 infection. However, children usually present mild symptoms compared to adult patients. The relationship between age, severity, and COVID-19 transmission is compared to determine whether there is any reasonable relationship between age and COVID-19. It should be mentioned that some risk factors may increase the&nbsp;probability of developing severe COVID-19 by advancing age, such as pathophysiological changes in the respiratory system, angiotensin-converting enzyme 2 expression in the nasopharynx, and smoking. Susceptibility to SARS-CoV-2 infection is independent of age, but the mortality rate of COVID-19 depends on age.</div> Adult, Aging, Children, SARS-CoV-2, COVID-19 241 246 http://ijml.ssu.ac.ir/browse.php?a_code=A-10-442-1&slc_lang=en&sid=1 Milad Zandi میلاد زندی miladzandi416@gmail.com 0000-0002-2145-0196 No Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Saber Soltani صابر سلطانی sabersoltani71@gmail.com 0000-0003-3369-0856 No Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mona Fani مونا فانی Fani.mona@yahoo.com No Department of Pathobiology and Laboratory Sciences, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran Department of Pathobiology and Laboratory Sciences, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran Haniye Shafipour honey.shafipour@gmail.com No Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Samaneh Abbasi s_abbasi80@yahoo.com Yes Department of Microbiology, Faculty of Medicine, Abadan University of Medical Sciences, Abadan, Iran