[Introduction to Infectious Disease Models] What is the difference between the April epidemic and this epidemic? .. .. ‼
Finally, the number of new infections has reached the world standard every day. As of July 31, 2020 (From the Ministry of Health, Labor and Welfare) Total number of infections; 35233 Severely ill; 80 Number of deaths; 1010 Number of new infections; 1574
However, the government is still watching, explaining that it is not at the stage of issuing a state of emergency. Reason ① There are few serious patients ② Medical facilities are not tight ．．． The following is not a direct reason not to declare, ③ It is necessary to turn the economy
It's a good idea, but it's a situation that ordinary people can't understand. Therefore, I would like to look at the above reasons from the data transition.
- It is one way to compare the situation in other countries, but this time I will look at the situation in Japan by data processing.
April epidemic and this epidemic
First, the comparison of one picture is as follows.
April epidemic
In the April epidemic, they visit in the following order: ① Increase in the number of new infections (blue bar graph) ② Increase in the number of existing infections (cases; red plot) ③ Delayed increase in cumulative number of cures (small green dot plot) and daily cures (large green plot) ④ Increase in cumulative deaths (blue plot) Continued. The delay in healing is estimated to be around 24-26 days and is expected to be discharged. The delay in the number of deaths is similar in the shape of the graph, aligning the top and bottom (looking at the mortality rate) (although it is necessary to shift the horizontal axis and estimate it to fit perfectly), roughly fit it between the eyes and about 10 It seems to be about a day (mortality rate 3-4%).
- It is necessary to scrutinize, but it is important to recognize that there is a delay and mortality rate here.
This fashion
If you draw a similar picture in this fashion, the situation will change completely.
(1) The increase in the number of new infections increases exponentially from around 20 (6/20)
(2) The number of existing infections (red plot) is increasing accordingly. It seems that the aftermath of the first wave remains before the 20th.
③ And the number of cures. In this epidemic, the cumulative number of cures (small green plot) and the number of daily cures (green plot) rise quickly and draw a curve that is almost the same as the number of existing infections. In addition, this cumulative number of cures has cleared 0 once as of 5/31 because I want to see only this epidemic.
④ The number of deaths has been more than 30 days since the start, but it is almost flat and has started to rise a little from 10 days ago, but the inclination is very small. It becomes parallel to the red plot in the steady state, but it seems that it is still ahead.
(** At this point, the mortality rate seems to be less than 1%, which can be said to be lower than in April **)
(5) The number of existing severe cases (black plot) has started to increase with the same shape as the number of existing infections (red plot). This is the nature as I mentioned the other day
If you look closely at the healing number curve
Therefore, I decided to repeat the number of new infections in this epidemic and the number of cures every day.
The results are as follows.
The picture below was obtained by shifting the number of cures to the left by 6 days each day.
If you shift it any further, the number of cures will exceed the number of new infections every day.
Also, if you shift it a little further to the right, it will be far below the number of new infections. In other words, it seems reasonable to think that many people are cured (discharged) with such a delay.
In honor of this point
① Mainly youth infection
② Many asymptomatic and mild
It seems that it is expressed by the expression.
And I think it is an assertion that this part is very different from the infection in April.
However, the number of existing infections (persons requiring hospitalization / monitoring) will not decrease as long as the infection spreads, and the work of medical and health centers will increase. In other words, the number of people on the right side of the green plot is clearly expanded when considering that the number of existing infections is the total number of monitoring targets such as hospitalization and waiting at home.
Forecast of future spread of infection
And above all, it is necessary to pay attention to the spread of the area and the age of infection, and roughly speaking, it is natural to think that if the spread of infection spreads, it will naturally spread to such areas and layers.
- Originally, I would like to do a time-series analysis of the spread of these regions and age groups, but I will not cover it in this article. So, here I would like to show the current status of the number of new infections. The spread of new infections is as follows, as of this writing. The analysis result about the trend is shown.
Nationwide
It is increasing steadily.
2000 people / day is just around the corner, and 5000 people / day are in sight.
The rate of increase is about 10 times / 30 days.
At the end of the month, it is predicted that there will be more than 10,000 people / day.
Tokyo
On the other hand, in Tokyo, the number of new infections was 463 on July 31, so it seemed to be negative once, but it has turned to an increasing trend.
However, the rate of increase is small, and it is predicted that this trend may be suppressed.
Most of all, the above negative tendency seems to be the effect of the small number of inspections, so it is an unpredictable situation.
Other than Tokyo
It can be predicted from the situation in Japan and Tokyo, but when actually calculated, it is a rapid increase.
The rate of increase is about 10 times / 25 days, and a simple calculation can predict that 10,000 people / day will be around 25 days. Before that, it is estimated that the number will increase to about 5,000 people / day at the end of the Bon Festival.
In other words, the epidemic is spreading in rural areas, and although not shown here, Regional expansion has also expanded the age group (young people). It is easy to imagine that there are also elderly people), and I am afraid of dangerous development in the future.
Summary
・ I compared the fashion in April with the fashion this time. ・ It was found that the cure number curve in this epidemic is significantly different from the April epidemic and the usual forecast. ・ The number of infections is forecast to increase significantly in rural areas, and it is feared that new infections will occur at 5,000 people / day at the beginning of the Obon festival and 10,000 people / day at the end of the month.
・ Although it is out of the scope of this article, healing in about 6 days is considered to mean that the monitoring period for asymptomatic and mildly ill patients is set to that extent, and it is necessary to discuss it. ・ I will try to evaluate the expansion of the region and the expansion of the age group by data analysis.
I put the code below
For data creation
COVID-19_Japan/test_pd.py It is a program that creates csv from the daily pdf released by the Ministry of Health, Labor and Welfare and processes them. Data other than Tokyo is created by manual processing on Excel.
For creating the entire graph
COVID-19_Japan/simple_draw_Japan.py
For creating an infection prediction graph
Created data (as of 7/31)
It is placed below Please judge the latest version and the April trend by upload date COVID-19_Japan/data
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