THE SIR MODEL ,SIR mass approximation
Budget: £10 – £20 GBP
You are asked to compare the spreading of a disease in a population when the value of R0 increases.
Use the SIR simulator written in Matlab (SIR_sim.mlx) by Giovanni Valentini.
In this simulator, the model parameters are as follow:
% Model parameters
beta = 5*10^-9; % rate of infection
gamma = 0.3; % rate of recovery (try also 0.3/0.2/0.12/0.07)
delta = 0.0; % rate of immunity loss
N = 6*10^7; % Total population N = S + I + R
I0 = 10; % initial number of infected
T = 300; % period of 300 days
dt = 1/4; % time interval of 6 hours (1/4 of a day)
fprintf('Value of parameter R0 is %.2f',N*beta/gamma)
and the value of R0 is calculated by N*beta/gamma.
In this exercise, you will alter the value of R0 by simply changing gamma while keeping
N and beta the same.
Setting gamma to 0.3, 0.2, 0.12 and 0.07, you will obtain R0 equals to 1, 1.5, 2.5 and 4.28 respectively.
The simulator presents three sets of results:
The first two sets are obtained from the basic SIR model (with no immunity loss) with the first graph showing the number of individuals in the S, I and R groups over time. The second graph shows the rate in which infection increases.
The last graph shows the number of individuals in S, I and R groups with the loss of immunity after 60 days.
Use the SIR simulator written in Matlab (SIR_sim.mlx) by Giovanni Valentini.
In this simulator, the model parameters are as follow:
% Model parameters
beta = 5*10^-9; % rate of infection
gamma = 0.3; % rate of recovery (try also 0.3/0.2/0.12/0.07)
delta = 0.0; % rate of immunity loss
N = 6*10^7; % Total population N = S + I + R
I0 = 10; % initial number of infected
T = 300; % period of 300 days
dt = 1/4; % time interval of 6 hours (1/4 of a day)
fprintf('Value of parameter R0 is %.2f',N*beta/gamma)
and the value of R0 is calculated by N*beta/gamma.
In this exercise, you will alter the value of R0 by simply changing gamma while keeping
N and beta the same.
Setting gamma to 0.3, 0.2, 0.12 and 0.07, you will obtain R0 equals to 1, 1.5, 2.5 and 4.28 respectively.
The simulator presents three sets of results:
The first two sets are obtained from the basic SIR model (with no immunity loss) with the first graph showing the number of individuals in the S, I and R groups over time. The second graph shows the rate in which infection increases.
The last graph shows the number of individuals in S, I and R groups with the loss of immunity after 60 days.