SIS: Simple SIS model (P 2.5).
In EpiDynamics: Dynamic Models in Epidemiology

Description Usage Arguments Details Value References See Also Examples

Solves a simple SIS model without births or deaths.

1	SIS(pars = NULL, init = NULL, time = NULL, ...)

`pars`	`vector` with 2 values: the transmission and recovery rates. The names of these values must be "beta", and "gamma", respectively.
`init`	`vector` with 2 values: the initial proportion of proportion of susceptibles and infectious. The names of these values must be "S" and "I", respectively.
`time`	time sequence for which output is wanted; the first value of times must be the initial time.
`...`	further arguments passed to ode function.

This is the R version of program 2.5 from page 39 of "Modeling Infectious Disease in humans and animals" by Keeling & Rohani.

All parameters must be positive and S + I <= 1.

list. The first element, *$model, is the model function. The second, third and fourth elements are the vectors (*$pars, *$init, *$time, containing the pars, init and time arguments of the function. The fifth element *$results is a data.frame with up to as many rows as elements in time. First column contains the time. Second and third columns contain the proportion of susceptibles and infectious.

Keeling, Matt J., and Pejman Rohani. Modeling infectious diseases in humans and animals. Princeton University Press, 2008.

ode.

# Parameters and initial conditions.
parameters <- c(beta = 1.4247, gamma = 0.14286)
initials <- c(S = 1 - 1e-06, I = 1e-06)

# Solve and plot.
sis <- SIS(pars = parameters, init = initials, time = 0:70)
PlotMods(sis)