Here is the true current coronavirus situation in USA, and hence you need to wear mask

 

 

We are using the date source from below two website

https://github.com/COVIDExposureIndices/COVIDExposureIndices

https://covidtracking.com

 

This site maintains a very complete and useful database of the percentage and number of cell phones logged in each state per day that have been logged in other states in the last 14 days, not only at the state level, but also at the county level.

Not only that, but also the website that maintains the daily number of tests and confirmed diagnoses per state. [covidtracking.com]

 

So what comes next can be repeated by anyone.

1, How far along is the current epidemic in the United States?

 

 

 

In terms of cumulative tests and cumulative confirmed diagnoses by state, the daily ratio of new confirmed diagnoses divided by new tests is not decreasing at all. We call this stage the "stable positive rate" stage, especially in New York State, where the positive rate remains stable between 30-40 percent to this day.

 

What does a steady 30%-40% positive rate mean? We can compare this with Italy, where the epidemic is currently killing the most people. The population of Italy is approximately three times that of New York State, and comparisons can be made on an order of magnitude, where we put on a graph the number of new tests and new confirmed diagnoses per day.

 

 

 

As can be seen, Italy (blue line) has seen a gradual decrease in the positivity rate after March 21 - the slope of the connecting line at each point and origin is getting lower and lower. on April 3, Italy's positivity rate dropped to 12 percent. But at the same time, New York State (red line) still has a 33% positive rate and is not trending down.

 

In order to make the epidemic comparable between the two regions, we started the calculation from the day when 2,000 people were diagnosed in New York State and 6,000 in Italy, and redrew the graph above to get the following graph.

 

 

In the graph above, the number next to each point represents the number of days when the number of confirmed cases in the region reached 1 in 10,000, which can be seen as the stage at which the epidemic developed in both regions at the same time. It can be seen that in Italy, after the number of confirmed cases reaches 1 in 10,000, it is not until the 22nd and 23rd day that the positive rate decreases significantly.

 

 

And one week after the number of confirmed cases reached 1 in 10,000, New York State's positive rate rose even further, moving farther and farther away from the same period in Italy.

 

 

The steady and high rate of positives means that the current outbreak in the United States is still in its infancy and daily confirmations will continue to rise. Referring to the trend in Italy, the United States has at least two weeks until the new period of confirmed stable diagnosis.

 

 

2, What is the actual number of infections in the United States?

 

we made several assumptions.

1, The spread of the epidemic in the United States began in New York and California, but the largest center of spread was in New York, so the history of travel in New York would be a very important variable. We calculated the New York sojourn history population for each state using the previous signaling data, and put it together with the number of infections in that state to get the following graph.

 

 

Shockingly, they really are on the line!

 

 

And California sojourners are not as effective as New York sojourners, especially in states like Michigan, New Jersey, and New York State, which currently have the highest number of diagnoses, and California is not in line with them.

 

Thus, New York State would be more persuasive as a diffusion center, and we next calculate the percentage of infections in New York's travel history to see how many people were actually infected in each state.

 

 

2, populations with a history of New York residency have the same prevalence of infection across regions.

 

 

In which areas is it easier to see accurate infection rates? I tried several options, the first was to separate the red states from the blue states, whichever was the red state - since there is relatively less history of New York sojourn in the red states, testing might be more targeted; the second was to separate the high positivity rate from the low positivity rate, whichever was the low positivity rate, since states with low positivity rates are less likely to reach test saturation. The two methods yielded similar results, namely the green line in the figure below.

 

 

 

The green line represents the actual number of infections per state as calculated using New York travel history. As can be seen, there are many other states that are some distance from the line, such as Vermont (VT), and New York State itself (NY). Based on the distance to the Green Line, New York State should currently have approximately 700,000 actual infections and is still 80 percent underdiagnosed. Meanwhile, the overall infection in the United States has reached 920,000 (on 5th,April).

 

If the U.S. does not reach the level of 100,000 new confirmed diagnoses per day for the next while, the epidemic will not get better.