Trend of case fatality rate during first 30 days of COVID-19 epidemic; the example of Iran

Khatereh Anbari,Seyyed Amir Yasin Ahmadi,Mitra Elmi

doi:10.34172/jpe.2020.05

Khatereh Anbari, Seyyed Amir Yasin Ahmadi + Show 1 more

Open Access

https://doi.org/10.34172/jpe.2020.05

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Abstract

Introduction: One of the unusual aspects in coronavirus disease 2019 (COVID-19) pandemic is changing case fatality rate (CFR) in different time series. Many researchers are trying to find the reasons of this variability. Objectives: This study aimed to present a model for a 30-day trend of CFR in any infectious disease epidemic using the example of COVID-19 in Iran. Patients and Methods: As a case study, we tried to use statistical mining of scientific databases. A descriptive approach with quantitative tools was conducted. The World Health Organization (WHO) database was used to access daily reports of CFR. Funnel plot and Z score were used to study and graph the trend. Results: During this period of time, a total of 20610 cases were confirmed based on real-time polymerase chain reaction (PCR). Among them, 1556 individuals died. Therefore, CFR was calculated as 7.549% (95% confidence intervals 7.189%-7.910%). This frequency was considered as the pooled frequency. Daily CFR with 95% CI was compared with the pooled frequency. Conclusion: In our case, the epidemic was started from high CFR due to low number of cases and testing only highly suspicious individuals. Then, the CFR was reduced due to increased number of patients and improvement in screening. Finally, CFR went back to its moderate rate due to the addition of the death numbers related to the cases of previous days.

Highlights

One of the unusual aspects in coronavirus disease 2019 (COVID-19) pandemic is changing case fatality rate (CFR) in different time series
The present study aimed to show the trend of CFR change and discuss the reasons for this change in order to reach a general model for such epidemics in the future
It indicates that at the start of each epidemic, the CFR is significantly higher than the pooled CFR

Summary

Introduction

One of the unusual aspects in coronavirus disease 2019 (COVID-19) pandemic is changing case fatality rate (CFR) in different time series. Objectives: This study aimed to present a model for a 30-day trend of CFR in any infectious disease epidemic using the example of COVID-19 in Iran. CFR went back to its moderate rate due to the addition of the death numbers related to the cases of previous days. The first well-known mutation in this family happened in 2002 that ended to the severe acute respiratory syndrome (SARS) [2]. The recent mutation occurred in 2019 [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] that became the cause of coronavirus disease of year 2019 (COVID-19). This virus has a capsid and is medium size. It is noted that this virus causes complications of the disease by locating on angiotensin converting enzyme (ACE) II, its main pathogenesis is yet to be examined [5]

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