Shekhar's Science Blog

Thursday, May 28, 2020

COVID Control in India: Doubling Period Hypothesis

COVID Control in India: Doubling Period Hypothesis

 

Dr Himanshu Shekhar

 

Introduction: The previous post on analysis of active cases in India gave insight into the current and desired value of doubling period of each parameter. It became obvious that subtraction of recovered cases and deceased cases from total confirmed cases gives active cases. The doubling period for Deceased should be very high (~ 20-25). The doubling period of confirmed cases must be moderate and preferably as high as possible. A reasonable value of 12-13 is prevailing at present, as discussed in previous posts. The doubling period of recovered cases should be as low as possible, but some finite feasible practical value may be assigned. It may be in the range of 5-8 in general. Considering various doubling period, analysis for hypothetical cases, using self-developed mathematical model, is conducted, using data from Aarogya Setu on 28.05.2020, as baseline.

Test Run: As per Aarogya Setu app, on 28.05.2020, total number of confirmed cases in India is 158323, total number of recovered cases are 67692 and total number of death till date is 4531. For a preliminary study, Doubling Period for Confirmed cases, recovery cases and death cases are taken as 13, 8 and 12, respectively. This is reference test case for mathematical model. Then variation of various parameters are shown in histogram, below.

 


 

The height of each column represents total number of confirmed cases, which is rising. Accordingly, the recovery figures are also rising. The death cases are also rising with time, but it is not visible predominantly due to small value, as compared to other parameters. The most surprising thing is reduction in active cases, which is visible from height of the green column, with progress of time. The current active cases on 28.05.2020, stands at 86100, which becomes 62595 on 17.06.2020, with this hypothesis.

 


 

For better appreciation of the conclusion, the histogram column for each day is separated and presented below. All four parameters are presented and the reduction in active cases over period of time is clearly visible.

The same can be appreciated with the simple x-y plot.

 

 


 

Analysis: When analysis is conducted by varying the parameters, it must be understood, that analysis has certain limitations. Here the doubling period of each type of case is independent of each other in calculation. They are combined to get the active cases at any date. One peculiarity of this independent of data is that if doubling period of death cases has increased, ideally, it is good sign. It indirectly indicates that number of deaths are not increasing at faster pace. But in this mathematical model, this results in increase in number of active cases on 17.05.2020. For example, for doubling period of death cases as 20, the number of active cases on 17.06.2020 becomes 67918, which is higher than what is calculated for doubling period of death as 12.

The most ideal situation is reduction in doubling period of recovery, which is practically attempted and which is supported in this mathematical model also. If the recovery period is reduced from 8 to 7.5, keeping all other doubling period as in previous section (12 for confirmed cases and 12 for deaths cases), the number of active cases on 17.06.2020 will drastically come down to 15701, as shown below.




Another control can be exercised by increasing doubling period of confirmed case. If other parameters are kept same, and doubling period of confirmed cases is changed to 15, the number of active cases on 17.06.2020 reduces to 1640. This is depicted below.




Conclusion: The doubling period for confirmed cases, recovered cases and death cases are adjusted to attain and predict turnaround using mathematical model. It is observed that the prediction for next 15 days can be easily done based on the practical values and a turnaround can be visible. The results are tabulated below.

 

Doubling Period (day)

Numbers of cases as on 17.06.2020

Confirmed cases

Recovered Cases

Deaths Cases

Confirmed cases

Recovered Cases

Death Cases

Active Cases

13

8

12

459904

382924

14385

62595

13

8

20

459904

382924

9062

67918

13

7.5

12

459904

429817

14385

15701

15

8

12

398949

382924

14385

1640

 




Dr Himanshu Shekhar

 


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