In this paper, we provided an analysis of incidence and mortality indicators on COVID-19 in countries with high-incidence. The number of total cases was reported by approximately 13.7 million and there were 445.2 thousand deaths due to COVID-19 until 10 August, 2020. This report shows that the average fatality rate of COVID-19 in 10 countries with high-incidence is almost 3.26%. Until August 10, 2020, about 20 million cases of COVID-19 with a total of 728 thousand deaths have been reported worldwide. This study indicates that these 10 countries were responsible for about 67% of COVID-19 cases and 60% of deaths.
Given the fatality rate in 10 countries with high-incidence, the highest value was obtained with 10.93% in Mexico, followed by 5.64% in Iran and 4.43 in Peru. Our study showed that until 10 August, Chile had the highest incidence rate with 1951 cases per 100,000 population. This rate is followed by 1496, 1428 and 1417 in the USA, Peru and Brazil, respectively. A comparison of mortality rate on COVID-19 in selected countries reveals that the highest mortality rate has existed in Peru with 63.22 deaths per 100,000 population. Then Chile, Brazil and the USA have the highest values with 52.71, 47.27 and 43.64. However, the analysis of daily data proves that Chile has the highest average daily on the incidence rate with 12.12, and Peru with 0.4 death per 100,00 population has the first rank on daily mortality rate. The second and third rank in terms of the daily incidence rate is related to Peru and Brazil, followed by the USA. Although India with 160 cases per 100,000 population for incidence rate and 3.22 death for mortality rate had the lowest value, it does not have the last rank in terms of fatality rate. The lowest value on the fatality rate is related to the Russian Federation and South Africa at 1.68% and 1.86%, respectively.
The fatality rate in COVID-19 is significantly lower than in SARS and MERS. Our analysis of the fatality rate in selected countries specified that the fatality rate is about 3.26% on average. While studies have reported a fatality rate of 9.6% and 36% for SARS and MERS (14–16). However, our study overestimated the fatality rate on COVID-19 for some countries. For example, it was estimated at 10.93% for Mexico and 5.64% in Iran. In these countries, all cases on COVID-19 have probably not been diagnosed, especially in countries where diagnostic testing technology was not available at the beginning of outbreak. Also, the incubation period in the COVID-19 is relatively long, so many cases at this disease do not show symptoms and go undiagnosed. Besides, a part of this variation on the fatality rate may be due to differences in population structure.
Based on the results, distinct patterns emerged for the trend of incidence cases in selected countries. The first group is countries whose trends on the weekly mean of incidence number are still increasing and has not reached its maximum. These countries are India, Colombia, Brazil and Mexico. Another group such as the Russian Federation, South Africa and Chile, at first touched a peak on the incidence number, and then this trend declined steadily until August 10. Some countries, such as the USA, Iran, and Peru, have a unique pattern. In these countries, initially the incidence number has increased with a steep slope, but it has become decreasing and this cycle has been repeated. This result indicated that the trend of COVID-19 in these countries can be a function of different variables, including decisions that policymakers make to control this disease, the geographical location and economic status in countries, the availability of the health system to respond to the disease and cultural characteristics. For instance, the rapid growth in incidence cases during the 5th to 7th week in Iran could be due to travel caused by the New Year festival holidays.
In this study, we had some limitations. One major limitation of this study relates to the reported data by the WHO. These data couldn't reflect the actual incidence cases due to a large number of hidden cases in COVID-19. Therefore, it is likely that our study underestimated the incidence rate in selected countries. Also, the fatality rate is likely to be overestimated, especially in Mexico and Iran. Because in these countries the actual cases of COVID-19 should probably be much higher than the reported cases. Another shortcoming of this study relates to the onset timing at the COVID-19 outbreak in chosen countries. The date of epidemy onset on COVID-19 varies in the selected countries. The comparison of disease trends at different dates could be associated with distorted results.