Last Update 2020-03-29

This is the daily updated version of "Understanding Epidemic Data and Statistics: A case study of COVID-19".
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Understanding Epidemic Data and Statistics:

A case study of COVID-19

Abstract

The 2019-Novel-Coronavirus (COVID-19) has affected 176 countries and out of about 593291 confirmed cases. Understanding the transmission dynamics of the infection in each country which affected on a daily basis and evaluating the effectiveness of control policies is critical for our further actions. To date, the statistics of COVID-19 reported cases show more than 80 percent of infected had a mild case of disease, while around 14 percent of infected experienced a severe one and about 5 percent are categorized as critical disease victims. Today's report (2020-03-28; daily updates in the prepared website) shows the confirmed cases of COVID-19 in US, Italy, China, and Spain are 101657, 86498 , 81897 and 65719; respectively. Calculating the total Case Fatality Rate (CFR) of Italy (2020-03-04), about 12.279192321135698% of confirmed cases passed away. Compared to South Korea's rate of 1.538121057873188% (7.983241799000237 times lower than Italy) and China's 4.053921086293418% (66.98544187376592% lower than Italy), the CFR of Italy is too high. There are some effective policies that yield significant changes in the trend of cases. The lockdown policy in China and Italy (the effect observed after 11 days), Shutdown of all non-essential companies in Hubei (the effect observed after 5 days), combined policy in South Korea and reducing working hours in Iran.

Introduction

Human coronaviruses (HCoV) which causes gastrointestinal and respiratory tract infections, were first introduced by the discovery of HCoV-229E and HCoV-OC43, from the nasal cavities of human patients with the common cold, in 1960s (Myint, 199419; Tyrrell & Bynoe, 196627). Other discovered human coronaviruses, which have involved serious respiratory tract infections, include SARS-CoV (2003), HCoV NL63 (2004), HKU1 (2005), MERS-CoV (2012), and the latest one, SARSCoV-2 (2019) resulting in Coronavirus disease (COVID-19) (Lim, Ng, Tam, & Liu, 201615; Syed, 202026). The name refers to the morphology of the virus, when viewed under 2D transmission electron microscopy (large pleomorphic spherical particles with bulbous surface) and stems from the Latin word "corona", meaning "crown"(Goldsmith et al., 20049). Concerning the risk factor, HCoVs vary significantly; from the relatively harmless ones (i.e., common cold) to the most lethal ones (MERS-CoV, with more than 30% mortality rate in the infected) (Fehr & Perlman, 20156). CoVs spread during cold seasons and cause colds with major symptoms, i.e., fever, sore throat, and less commonly pneumonia and bronchitis for the more aggressive strains. To date, there are no vaccines or antiviral drugs capable of preventing or treating HCoV infections (Fehr & Perlman, 2015 6; Forgie & Marrie, 2009 8; Liu et al., 2017 16).
To date, several outbreaks of coronavirus-related diseases have been reported. Severe acute respiratory syndrome- or SARS was the first coronavirus-related outbreak, starting in Guangdong, China, in November 2002, and spread to a total of 29 territories, including Hong Kong, Taiwan, Canada, Singapore, Vietnam, and the United States, within 9 months. It infected a total of 8,098 people and killed 774 worldwide (Smith, 200625). The second coronavirus-related outbreak happened in the Middle East in April 2012, officially named Middle East Respiratory Syndrome or MERS. This virus was first identified in a patient from Saudi Arabia, and later, MERS affected several other countries, including Saudi Arabia, South Korea, the United Arab Emirates, Jordan, Qatar, and Oman. Overall resulting with infections in 24 countries, with over 1,000 cases and over 400 deaths (Organization23). The outbreak of MERS happened again in South Korea, supposedly from a traveler from Middle East. It happened during May and July 2015, and infected a total of 186 individuals, with a death toll of 36 (Organization, 201524). After 3 years in August 2018, the next MERS outbreak happened in countries on the Arabian Peninsula, and resulted in almost 147 infected people and the death of 47. The MERS outbreak had been reported in Saudi Arabia, United Kingdom, and South Korea.
In Dec 2019, a pneumonia outbreak was reported in Wuhan, China, and on Dec 31, it was attributed to a new strain of HCoV, first named as 2019-nCoV by World Health Organization (WHO), and later renamed to SARS-CoV-2 by the International Committee on Taxonomy of Viruses. Almost 2 weeks later, on Jan. 11, 2020, Chinese state media reported the first fatality from the new discovered virus, that led to infection of dozens more (https://www.nytimes.com/2020/01/10/world/asia/china-virus-wuhan-death.html). As of Jan 20, multiple countries reported their first cases, including Japan, South Korea and Thailand. The first confirmed case in the United States came the very next day in Washington State. Continuing its spread, Coronavirus presence was confirmed throughout the month of February in the Philippines (Feb 2), France (Feb 14), Iran (Feb 21), and as reports started in Italy on Feb 23; many more Europeans countries followed suit, reporting their first confirmed cases. As of this writing, the coronavirus has affected 176 countries, out of about 593291 confirmed cases, around 4,000 people have lost their lives. With China, Italy, Iran, and South Korea experiencing the worst cases of outbreaks and showing no sign of alleviation, the 2019-2020 outbreak of COVID-19 is now officially recognized as a pandemic by WHO. An outbreak or epidemic often refers to a sudden increase in the occurrence of an infectious disease, in a particular time and place. Pandemics are near-global epidemic outbreaks, where multiple countries across the world are involved (Green et al., 200211).
The mentioned rapid trend of spread prompts a lot of concerns and questions such as; "How fast is the virus spreading?", "which policies or efforts could control the disease better?", and "what is the main difference of COVID-19 outbreak with pervious epidemics?" Fortunately, the daily case detection changes are available and can be tracked almost in real time on the website provided by authors (http://iuwa.ir/corona/). The aim of this study is to provide the transmission trend from China to other countries and to report the daily confirmed cases, case fatalities and surveillance in every countries from the first day of outbreak until (2020-03-28). Also, to evaluate the effect of each government policies in controlling the outbreak of COVID-19.

Basic Statistics

COVID-19 has currently spread to 176 countries and most national authorities have failed to keep it's rapid spread contained 32. WHO (World Health Organization) reports that it began in Wuhan city, located in Hubei Province of China, first reported on 21 January 20. COVID-19 categorizes in three distinctions concerning it's infected host's severity of disease 10,17. To date, the statistics of its reported cases shows more than 80 percent of infected had a mild case of disease, while around 14 percent of infected experienced a severe one, suffering from breathlessness and pneumonia. And about 5 percent are categorized as critical disease patients, their symptoms include septic shock, respiratory failure, and the failure of more than one organ.
Today's (2020-03-28) reports show that US has the most confirmed, fatal and also recovered cases. The order of confirmed cases after China's, is followed respectively by Italy, China, and Spain; which could be found in the table1.

Table 1

Top 10 total Confirmed, Deaths & Recovered cases

Country/Region Confirmed Deaths Recovered
0 US 101657 1581 869
1 Italy 86498 9134 10950
2 China 81897 3296 74720
3 Spain 65719 5138 9357
4 Germany 50871 342 6658
5 France 33402 1997 5707
6 Iran 32332 2378 11133
7 United Kingdom 14745 761 151
8 Switzerland 12928 231 1530
9 Korea, South 9332 139 4528

Confirmed death cases caused by COVID-19 are also observed in 109 different countries, lead in numbers by Italy, Spain, China, and Iran respectively. About 5.812927421133907% of death cases are located in US, 17.13442475951936 % of confirmed cases are located in US (0.6650900435484735% of recovered cases are located in China) were also present table1. Countries reported that all infected cases were recovered and there are no active cases that exist in their databases table2.

Table 2

Countries with no active cases

Country/Region Confirmed Recovered Deaths

The overall stats states that there are 593291 confirmed, 27198 deaths and 130659 recovered cases.
Figure 1 also shows that the COVID-19 spread exists in all continents.

Figure 1

Transmission of Coronavirus Disease 2019-2020 (COVID-19); Blue nodes represents regions with confirmed COVID-19 cases, and Red nodes represents the regions with COVID 19 causes deaths

Heatmap of Confirmed Cases

Heatmap of Death Cases

Finding Linear Relations

There isn't much known at the moment about COVID-19, so there is a small amount of data about its comprehensive effects and behaviors. In this study, relations are assumed to be linear, when, initially the drawn plot shows obvious linear relations and secondly, the fitted linear regression line had a small enough error to preserve the values given and the linear regression results could be interpreted with relative ease. In addition, by fitting regression lines with higher order, causes overfitting, resulting from the amount of data. There is no evidence yet, about the relation of other conditions to the outbreak and its case fatality rate (CFR), so by using linear regression line, policies and behaviors could be compared. In the prediction cases, by using linear regression, we could compare future trends of countries in earlier stages, with the ones in later stages. By considering above mentioned statements, we will find the best linear relation between arrays of data. In some cases, the linear relation could be observed but it may exhibit linear relation with some date shift of others (i.e. death cases should have linear relation with earlier values of confirmed cases, given the fact that it should take time from confirmation to death.)
CFR could be calculated by the following formula: $$CFR=\dfrac{D_{eath}(T)}{C_{onfirmed}(T-dt)}$$ In which Death and Confirmed functions will calculate the value of death cases and confirmed cases at that date, T being the date we want to inspect the CFR, dt is the mean duration of confirmed to death.

Global Daily Statistics

Figure 2

COVID-19 global epidemic data and statistics of. a) confirmed, recovered and death COVID-19 cases, b) normalized confirmed, recovered and death COVID-19 cases, c) New confirmed, recovered and death COVID-19 cases, and d) Normalized new confirmed, recovered and death COVID-19 cases

Figure 2 shows the global confirmed, deaths and recovered cases' trend for COVID-19 form Jan 22 to 2020-03-28. Death cases are excessively lower than confirmed ones, so we normalized (By dividing the value of Confirmed, Deaths and Recovered cases to their maximum respectively.) it in above Fig. to investigate all three trends of cases. For the confirmed cases, there is a huge increase since Feb 11, the increase tones down from Feb 11 to the next day, Furthermore on Feb 13 another sharp increase is reported. It could be observed in Fig. 2 which shows new cases for each day (and normalized in Fig. 2 ). The most reliable speculation for this jump is that in that day, China (the country with the most confirmed cases) for the first time, reported the clinically diagnosed cases in addition to laboratory-confirmed cases 21, in which 13332 clinically diagnosed cases are added to 1148 laboratory-confirmed ones. Since then, China has kept the same reporting method for the confirmed cases. On 23rd and 24th of Feb, again the decrease of new cases subsided and new cases increased as before. As shown in Fig. 2 the reduction trend is continued (approximately) and the cause of the increase was other countries' growing numbers. So, for more accurate analysis each country will be investigated separately.

China Daily Statistics

Figure 3

COVID-19 epidemic data and statistics of China (main land), Hubei province, and China excluding Hubei a-c) New confirmed, recovered and death COVID-19 cases, d-f) Normal data for confirmed, recovered and death COVID-19 cases, g-i) Confirmed and Death cases, and j-l) Normal data of confirmed and death cases