Coronaviruses are a big family of viruses. Some coronaviruses cause diseases in human and some others in animals such as bats and camels. Human coronaviruses typically cause mild diseases. Sometimes, animal coronaviruses evolve and spread among humans and cause severe diseases; Severe Acute Respiratory Syndrome (SARS) in 2002 and Middle East Respiratory Syndrome (MERS) in 2012 were among such cases [1–3]. Coronavirus 2019-nCoV is a new species of this virus which had not been identified in human before. This virus was first identified in Wuhan city in China in December of 2019 and had a widespread outbreak. This virus had a more widespread outbreak in China and until March 14th 2020, in more than 130 countries, positive cases of that were reported [1, 4]. According to the published world statistics, the number of identified people infected by coronavirus was 145332 (until March 14th 2020) out of which 70921 people were recovered and 5416 people died; the reported fatality rate of this disease among people has been 3.7% so far. According to the existing evidences, the emergence of this disease in almost 91% of people is mild and in 9% is severe [5].
In Iran, the first positive case of Coronavirus 2019-nCoV was confirmed in February 20th 2020 in Qom city and until March 14th 2020, the total number of cases in the country was 11364 people out of which 3529 people were recovered and 514 people died [6]. According to world statistics, up to now, Iran has reported the most positive cases of coronavirus after China (80815) and Italy (17660) [5].
One of the most important indices noticed by healthcare experts, policymakers and managers in epidemics, specifically in emerging epidemics, is CFR index. This index is obtained by dividing the death toll caused by a disease by the total number of people infected by the same disease. In most cases, this index is utilized for specific epidemics of acute diseases such as cholera during which all patients are under treatment in a specific period of time and this makes it possible to calculate the death toll caused by a disease. The index of CFR indicates the fatality potential of a disease and it just includes the proportion of death toll to the number of patients. This index can be used to describe fatality trend and its general changes, making decisions for healthcare priorities, resource allocation, planning intervention programs and evaluation and refining problems and plans for public health and it can terrify a society in case of emerging epidemics when it is reported high [8, 7]. In Iran and many other countries, in the outbreak or in the middle of Covid19, some interpretations were put on CFR. These interpretations were sometimes published on social news networks and cause fear among people and put pressure on countries’ health system. In Iran, given the fact that in the outbreak, this index was high, there were different interpretations on the fatality rate of this disease and based on that, different judgments were made concerning the health systems. In this study, we were in search of this index trend during different time intervals of this epidemic’s outbreak. In other words, this study made an effort to answer the following question: Is it right to base judgment on CFR at each stage during epidemics and is it right to judge based on that since the outbreak of an epidemic?