Coronavirus disease is caused by a virus that is the cause of a potentially fatal disease worldwide. Coronavirus is a pathogen that primarily affects the human respiratory system. Coronavirus 2019 (COVID-19) has been named WHO since February 11, 2020. The fi rst cases of COVID-19 were reported in December 2019. In January 2020, COVID-19 infection was identifi ed in hospitalized patients in Wuhan, China. We analyze the role of neutrophil-lymphocyte ratio (NLR) in viral infection with special emphasize on novel corona virus disease-COVID-19. NLR may be used for early detection and may refl ect progression to the more severe illness leading to SARS-CoV-2. In the mini review we investigate the use of NLR as a surrogate marker for diagnosis and stratifi cation of COVID-19. Clinical symptoms such as pneumonia, acute respiratory distress syndrome, acute heart damage have led to death. In some cases, multiple infl ammations have been observed. Treatment with interferon inhalation showed no clinical effect and the condition worsened instead (Tab. 5, Fig. 1, Ref. 18).