Package 'facilityepimath'

Title: Analyze Mathematical Models of Healthcare Facility Transmission
Description: Calculate useful quantities for a user-defined differential equation model of infectious disease transmission among individuals in a healthcare facility. Input rates of transition between states of individuals with and without the disease-causing organism, distributions of states at facility admission, relative infectivity of transmissible states, and the facility length of stay distribution. Calculate the model equilibrium and the basic facility reproduction number, as described in Toth et al. (2025) <doi:10.1101/2025.02.21.25322698>.
Authors: Damon Toth [aut, cre, cph] , Centers for Disease Control and Prevention [fnd] (Modeling Infectious Diseases in Healthcare Network award number U01CK000585)
Maintainer: Damon Toth <[email protected]>
License: MIT + file LICENSE
Version: 0.1.0
Built: 2025-03-07 13:31:51 UTC
Source: CRAN

Help Index


Calculate the equilibrium of a linear facility model

Description

Calculate the equilibrium of a linear facility model

Usage

equilib(M, init, mgf = NULL)

Arguments

M

A matrix of state transition rates between facility patient states

init

A vector of admission state probabilities to each state

mgf

The moment generating function characterizing a time-of-stay-dependent removal hazard

Value

A vector with the proportion of patients in each state at equilibrium

Examples

M <- rbind(c(-0.06,0.03,0),c(0.06,-0.08,0),c(0,0.05,0))
init <- c(0.95,0.05,0)
mgf <- function(x, deriv=0) MGFgamma(x, rate = 0.05, shape = 2.5, deriv)
equilib(M, init, mgf)

Calculate the equilibrium of a facility transmission model

Description

Calculate the equilibrium of a facility transmission model

Usage

facilityeq(S, C, A, R, transm, init, mgf = NULL)

Arguments

S

A matrix of state transition rates between and removal from the susceptible states in the absence of colonized individuals

C

A matrix of state transition rates between and removal from the colonized states

A

A matrix describing transitions from susceptible to colonized states at acquisition

R

A matrix of recovery rates: state transition rates from colonized to susceptible states

transm

A vector of transmission rates from each colonized state

init

A vector of admission state probabilities to each state

mgf

The moment generating function characterizing a time-of-stay-dependent removal hazard

Value

A vector with the proportion of patients in each state at equilibrium; the vector contains the equilibrium S states followed by C states

Examples

S <- 0
C <- rbind(c(-0.38,0),c(0.08,0))
A <- rbind(1,0)
R <- cbind(0.3,0)
transm <- c(0.1,0.05)
init <- c(0.99,0.01,0)
mgf <- function(x, deriv=0) MGFgamma(x, rate=0.2, shape=3, deriv)
facilityeq(S, C, A, R, transm, init, mgf)

Calculate basic reproduction number R0

Description

Calculate basic reproduction number R0

Usage

facilityR0(S, C, A, transm, initS, mgf = NULL)

Arguments

S

A matrix of state transition rates between and removal from the susceptible states in the absence of colonized individuals

C

A matrix of state transition rates between and removal from the colonized states

A

A matrix describing transitions from susceptible to colonized states at acquisition

transm

A vector of transmission rates from each colonized state

initS

A vector of admission state probabilities to each susceptible state

mgf

The moment generating function characterizing the time-of-stay-dependent removal hazard

Value

A number (R0)

Examples

S <- rbind(c(-1,2),c(1,-2))
C <- rbind(c(-1.1,0),c(0.1,-0.9))
A <- rbind(c(1,0),c(0,2))
transm <- c(0.4,0.6)
initS <- c(0.9,0.1)
mgf <- function(x, deriv=0) MGFgamma(x, rate=0.01, shape=3.1, deriv)
facilityR0(S,C,A,transm,initS,mgf)

Calculate the mean length of stay for a linear facility model

Description

Calculate the mean length of stay for a linear facility model

Usage

meanlengthofstay(M, init, mgf)

Arguments

M

A matrix of state transition rates between facility patient states

init

A vector of admission state probabilities to each state

mgf

The moment generating function characterizing a time-of-stay-dependent removal hazard

Value

The mean length of stay

Examples

M <- rbind(c(-1.1,2),c(1,-2.2))
init <- c(0.9,0.1)
mgf <- function(x, deriv=0) MGFgamma(x, rate=0.2, shape=3, deriv)
meanlengthofstay(M, init, mgf)

Evaluate the moment generating function (MGF) of the exponential distribution or a derivative of the MGF

Description

Evaluate the moment generating function (MGF) of the exponential distribution or a derivative of the MGF

Usage

MGFexponential(x, rate, deriv = 0)

Arguments

x

The value at which to evaluate the MGF

rate

The rate parameter value of the exponential distribution

deriv

An integer, the number of derivatives of the MGF to apply

Value

The number resulting from the function evaluation

Examples

# MGF of an exponential distribution, evaluated at -0.1:
MGFexponential(-0.1, rate = 0.05)
# Second moment of the distribution (second derivative evaluated at zero):
MGFexponential(0, rate = 0.05, deriv = 2)

Evaluate the moment generating function (MGF) of the gamma distribution or a derivative of the MGF

Description

Evaluate the moment generating function (MGF) of the gamma distribution or a derivative of the MGF

Usage

MGFgamma(x, rate, shape, deriv = 0)

Arguments

x

The value at which to evaluate the MGF

rate

The rate parameter value of the gamma distribution

shape

The shape parameter values of the gamma distribution

deriv

An integer, the number of derivatives of the MGF to apply

Value

The number resulting from the function evaluation

Examples

# MGF of a gamma distributions, evaluated at -0.1:
MGFgamma(-0.1, rate = 0.7, shape = 3)
# Second moment of the distribution (second derivative evaluated at zero):
MGFgamma(0, rate = 0.7, shape = 3, deriv = 2)

Evaluate the moment generating function (MGF) of the mixed gamma distribution or a derivative of the MGF

Description

Evaluate the moment generating function (MGF) of the mixed gamma distribution or a derivative of the MGF

Usage

MGFmixedgamma(x, prob, rate, shape, deriv = 0)

Arguments

x

The value at which to evaluate the MGF

prob

A vector of probabilities of following each gamma distribution in the mixture

rate

A vector of rate parameter values for each gamma distribution in the mixture

shape

A vector of shape parameter values for each gamma distribution in the mixture

deriv

An integer, the number of derivatives of the MGF to apply

Value

The number resulting from the function evaluation

Examples

# MGF of a 40/60 mixture of two gamma distributions, evaluated at -0.1:
MGFmixedgamma(-0.1, prob = c(0.4,0.6), rate = c(0.4,0.7), shape = c(0.5,3))
# Second moment of the distribution (second derivative evaluated at zero):
MGFmixedgamma(0, prob = c(0.4,0.6), rate = c(0.4,0.7), shape = c(0.5,3), deriv = 2)