Abstract
Coronavirus disease 2019 (COVID-19) outbreak is proving to be an unprecedented disaster that lays its dark shadow on global health, economics and personal freedom. Severe acute respiratory syndrome (SARS) and middle east respiratory syndrome (MERS) epidemics provide scientific data that is useful in better understanding and resolution of COVID-19. Similarities among SARS-CoV, MERS-CoV and SARS-CoV-2 have been investigated in the light of available data. SARS-CoV, MERS-CoV and SARS-CoV-2 evolved in bats and have positive-sense RNA genomes of 27.9 kb, 30.1 kb and 29.9 kb, respectively. Molecular and serological tools used for diagnosis of SARS and MERS patients resemble COVID-19 diagnostic tools. Stability and longevity data of SARS and MERS epidemics contribute in the current pandemic precaution policies. Trials to produce vaccines for SARS-CoV and MERS-CoV failed, therefore different strategies were employed for SARS-CoV2 vaccines production and during the past period antiviral agents, Convalescent plasma and monoclonal antibodies provide potential treatments for sever patients. The mortality rate caused by the SARS-CoV and MERS-CoV reached 15% and 37%, respectively. The first declarations about mortality rate of SARS-CoV-2 was around 2-4% but now this rate differed globally and reached more than 13% in some countries. A realistic COVID-19 outbreak scenario suggest that the pandemic might last for three years with fluctuation in the number of infected cases, unless vaccination process goes faster and/or antiviral drug is discovered.