Fig. 10

The analysis of the average daily increment, per 7 days, in different countries and regions. *One unit of the abscissa was a week (7 days). It set the day when the new cases exceeded 20 as the starting point. According to the regional division in the WHO report, this figure included the top 6–10 countries of each region, for which the daily increase exceeded 20, to show the trends of confirmed cases. Countries meeting this condition in the Southeast Asia region and Western Pacific region were just 6 and 8, respectively, both less than 10. The countries in parts a and e were closer to the equator with slow growth or at the early stage of infections. In parts b and d, most countries were in the rapid growth phase, as well as Russian in part c. Dividing the average daily increment value of the final week by the previous week, to get the change coefficient for each country here. The average change coefficient value of the countries in a region was used to evaluate the growing speed of a region. The average change coefficient was 1.3 in the Eastern Mediterranean region and 1.25 in the region of the Americas. Besides, the change coefficient was 1.3 in Russian. Most European countries in part c as well as the USA in part d presented an inflection point or at a plateau period in the fourth to fifth weeks but declined slowly. Germany, Spain, Italy, and China (a) took 28, 29, 34, and 18 days, respectively, to reach their peak daily increments. China (b) took 27 days as it contained an increase in clinical diagnoses published in the fifth week. The curve of China dropped rapidly after the fifth week. The two stars in the curve of China indicate the start of reporting imported cases from abroad (starting on February 26) in mainland China (excluding Hong Kong, Macao and Taiwan) and the response of suspending entry of foreigners holding valid Chinese visas and residence permits (March 28). From February 26 to April 21, mainland China reported approximately 1610 imported cases from abroad, approximately 3 times the Sichuan cumulative cases. During that time, there were 174 newly confirmed local cases in mainland China. All the newly confirmed case numbers were in the period up to April 21 in this figure