Chime model - SIR calculation

[dzak1234]

Hello,

I am testing the following set of parameters:

Currently Hospitalized COVID-19 Patients 69
Doubling time before social distancing (days) 4
Social distancing (% reduction in social contact) 30%
Hospitalization %(total infections) 2.5%
ICU %(total infections) 0.75%
Ventilated %(total infections) 0.5%
Hospital Length of Stay 7
ICU Length of Stay 9
Vent Length of Stay 10
Hospital Market Share (%) 15%
Regional Population 100,000

My t = 0 numbers are:
Susceptible: 71,290
Infected: 19,653
Recovered: 9,055

Given the above initial set of inputs/parameters, I get the following parameters after application of social distancing: beta = 0.00000182445, gamma = 0.071429 (assuming 14 days for recovery). Therefore, my number of infected people during t=1 should be:
I(1) = (S(0)betaI(0)-gamma*I(0)) + I(0) = (71,290 * 0.00000182445 * 19,653 - 0.071429 * 19,653) + 19,653 = 20,805

However, when I plug in the initial parameters into your CHIME model, I get infected people at t = 1 to be 20,813. I realize that the difference is small, however, the difference diverges the further out in time I go.

Any thoughts would be greatly appreciated.

Thank you.

[dzak1234]

Hello, just wanted to circle back and see if there are any thoughts regarding this. Thank you.

[ManuTel]

hi @dzak1234 I have one query that I think you can answer. Given the input, you arrive at the following SIR at t=0

My t = 0 numbers are:
Susceptible: 71,290
Infected: 19,653
Recovered: 9,055

Can you please explain how CHIME estimates the t=0 numbers for infected and recovered?
Thanks in Advance. I tried to do manual calculations but failed.