Background: During the current Covid-19 pandemic case fatality rate (CFR) estimates were subjected to a lot of debates regarding the accuracy of its estimations, predictions, and the reason of across countries variances . In this context, we conduct this study to see the relationship between attack rate (AR) and CFR . The study hypothesis is based on two : 1- evidence suggests that the mortality rate (MR) has a positive influence on case fatality ratio (CFR), 2- and increase number of Covid-19 cases leads to increased mortality rate (MR). Material and methods: Thirty countries and territories were chosen . Inclusion criterion was> 500 Covid-19 reported cases per 10,000 population inhabitants . Data on covid-19 cases and deaths was selected as it was on March 10 , 2021 . Statistical methods used are descriptive and one-sample Kolmogorov-Smirnov (K-S), the one-way ANOVA, Levene, least significant different (LSD), and matched paired-samples T-tests .
Results: ANOVA test showed a significant difference at P <0.01 among all studied groups concerning AR and CFR mean values . Group of countries with MR [≥] 15 death / 104 inhabitants recorded the highest level of crude mean CFR and AR values, and recorded the highest gap with leftover groups, especially with countries reported MR of <10 death/ 104 inhabitants . There were independence 95% confidence intervals of mean CFR and AR values between countries with [≥] 15 death / 104 MR and countries with MR of <10 death /104 . There was a significant difference between countries with MR [≥] 15 death / 104 inhabitants and countries with MR of <10 death / 10 4 inhabitants groups through least significant difference (LSD) test for CFR% (0.042 p-values) and Games Howell (GH) test for AR/104 (p-value 0.000).
Conclusions: CFR has a positive significant association with AR.