This R package is a wrapper of the C++ library epiworld. It provides a general framework for modeling disease transmission using agent-based models. Some of the main features include:
- Fast simulation with an average of 30 million agents/day per second.
- One model can include multiple diseases.
- Policies (tools) can be multiple and user-defined.
- Transmission can be a function of agents’ features.
- Out-of-the-box parallelization for multiple simulations.
From the package’s description:
A flexible framework for Agent-Based Models (ABM), the epiworldR package provides methods for prototyping disease outbreaks and transmission models using a C++ backend, making it very fast. It supports multiple epidemiological models, including the Susceptible-Infected-Susceptible (SIS), Susceptible-Infected-Removed (SIR), Susceptible-Exposed-Infected-Removed (SEIR), and others, involving arbitrary mitigation policies and multiple-disease models. Users can specify infectiousness/susceptibility rates as a function of agents’ features, providing great complexity for the model dynamics. Furthermore, epiworldR is ideal for simulation studies featuring large populations.
You can install the development version of epiworldR from GitHub with:
devtools::install_github("UofUEpiBio/epiworldR")Or from CRAN
install.packages("epiworldR")This R package includes several popular epidemiological models including SIS, SIR, and SEIR using either a fully connected graph (similar to a compartmental model) or a user-defined network. Here are some examples:
This Susceptible-Infected-Recovered model features a population of 100,000 agents simulated in a small-world network. Each agent is connected to ten other agents. One percent of the population has the virus, with a 70% chance of transmission. Infected individuals recover at a 0.3 rate:
library(epiworldR)
# Creating a SIR model
sir <- ModelSIR(
name = "COVID-19",
prevalence = .01,
transmission_rate = .7,
recovery = .3
) |>
# Adding a Small world population
agents_smallworld(n = 100000, k = 10, d = FALSE, p = .01) |>
# Running the model for 50 days
run(ndays = 50, seed = 1912)
#> _________________________________________________________________________
#> |Running the model...
#> |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| done.
#> | done.sir
#> ________________________________________________________________________________
#> Susceptible-Infected-Recovered (SIR)
#> It features 100000 agents, 1 virus(es), and 0 tool(s).
#> The model has 3 states.
#> The final distribution is: 822 Susceptible, 415 Infected, and 98763 Recovered.Visualizing the outputs
summary(sir)
#> ________________________________________________________________________________
#> ________________________________________________________________________________
#> SIMULATION STUDY
#>
#> Name of the model : Susceptible-Infected-Recovered (SIR)
#> Population size : 100000
#> Agents' data : (none)
#> Number of entities : 0
#> Days (duration) : 50 (of 50)
#> Number of viruses : 1
#> Last run elapsed t : 165.00ms
#> Last run speed : 30.13 million agents x day / second
#> Rewiring : off
#>
#> Global events:
#> (none)
#>
#> Virus(es):
#> - COVID-19 (baseline prevalence: 1.00%)
#>
#> Tool(s):
#> (none)
#>
#> Model parameters:
#> - Recovery rate : 0.3000
#> - Transmission rate : 0.7000
#>
#> Distribution of the population at time 50:
#> - (0) Susceptible : 99000 -> 822
#> - (1) Infected : 1000 -> 415
#> - (2) Recovered : 0 -> 98763
#>
#> Transition Probabilities:
#> - Susceptible 0.91 0.09 0.00
#> - Infected 0.00 0.70 0.30
#> - Recovered 0.00 0.00 1.00plot(sir)
The SEIR model is similar to the SIR model but includes an exposed state. Here, we simulate a population of 10,000 agents with a 0.01 prevalence, a 0.6 transmission rate, a 0.5 recovery rate, and 7 days-incubation period. The population is fully connected, meaning agents can transmit the disease to any other agent:
model_seirconn <- ModelSEIRCONN(
name = "COVID-19",
prevalence = 0.01,
n = 10000,
contact_rate = 4,
incubation_days = 7,
transmission_rate = 0.6,
recovery_rate = 0.5
) |> add_virus(virus("COVID-19", 0.01, 0.6, 0.5, 7), .5)
set.seed(132)
run(model_seirconn, ndays = 100)
#> _________________________________________________________________________
#> Running the model...
#> ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| done.
#> done.model_seirconn
#> ________________________________________________________________________________
#> Susceptible-Exposed-Infected-Removed (SEIR) (connected)
#> It features 10000 agents, 2 virus(es), and 0 tool(s).
#> The model has 4 states.
#> The final distribution is: 634 Susceptible, 5 Exposed, 0 Infected, and 9361 Recovered.Computing some key statistics
plot(model_seirconn)
repnum <- get_reproductive_number(model_seirconn)
head(plot(repnum))
#> virus_id virus date avg n sd lb ub
#> 1 0 COVID-19 0 2.762500 80 2.082135 1.0 7.025
#> 2 0 COVID-19 2 3.250000 24 2.862805 0.0 9.850
#> 3 0 COVID-19 3 3.294118 17 2.663755 0.4 9.400
#> 4 0 COVID-19 4 2.666667 18 2.351470 0.0 7.875
#> 5 0 COVID-19 5 1.878788 33 1.745666 0.0 5.800
#> 6 0 COVID-19 6 1.794118 34 1.533058 0.0 4.350
plot_incidence(model_seirconn)
head(plot_generation_time(model_seirconn))
#> date avg n sd ci_lower ci_upper virus virus_id
#> 1 2 8.400000 20 6.227274 2.475 24.150 COVID-19 0
#> 2 3 8.750000 16 6.547264 2.375 21.750 COVID-19 0
#> 3 4 7.625000 16 5.302515 2.375 19.000 COVID-19 0
#> 4 5 5.888889 27 3.178453 2.000 12.700 COVID-19 0
#> 5 6 10.148148 27 5.586410 2.000 21.400 COVID-19 0
#> 6 7 8.458333 24 6.064717 2.000 20.825 COVID-19 0
This model provides a more complex transmission and recovery pattern
based on agents’ features. With it, we can reflect co-morbidities that
could change the probability of infection and recovery. Here, we
simulate a population including a dataset with two features: an
intercept and a binary variable Female. The probability of infection
and recovery are functions of the intercept and the Female variables.
The following code simulates a population of 100,000 agents in a
small-world network. Each agent is connected to eight other agents. One
percent of the population has the virus, with an 80% chance of
transmission. Infected individuals recover at a 0.3 rate:
# Simulating a population of 100,000 agents
set.seed(2223)
n <- 100000
# Agents' features
X <- cbind(
Intercept = 1,
Female = sample.int(2, n, replace = TRUE) - 1
)
coef_infect <- c(.1, -2, 2)
coef_recover <- rnorm(2)
# Creating the model
model_logit <- ModelSIRLogit(
"covid2",
data = X,
coefs_infect = coef_infect,
coefs_recover = coef_recover,
coef_infect_cols = 1L:ncol(X),
coef_recover_cols = 1L:ncol(X),
prob_infection = .8,
recovery_rate = .3,
prevalence = .01
)
# Adding a small-world population
agents_smallworld(model_logit, n, 8, FALSE, .01)
# Running the model
run(model_logit, 50)
#> _________________________________________________________________________
#> |Running the model...
#> |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| done.
#> | done.plot(model_logit)
# Females are supposed to be more likely to become infected
rn <- get_reproductive_number(model_logit)
(table(
X[, "Female"],
(1:n %in% rn$source)
) |> prop.table())[,2]
#> 0 1
#> 0.12984 0.14201# Looking into the agents
get_agents(model_logit)
#> Agents from the model "Susceptible-Infected-Removed (SIR) (logit)":
#> Agent: 0, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 1, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 2, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 3, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 4, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 5, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 6, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 7, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 8, state: Susceptible (0), Has virus: no, NTools: 0i NNeigh: 8
#> Agent: 9, state: Recovered (2), Has virus: no, NTools: 0i NNeigh: 8
#> ... 99990 more agents ...This example shows how we can draw a transmission network from a simulation. The following code simulates a population of 500 agents in a small-world network. Each agent is connected to ten other agents. One percent of the population has the virus, with a 50% chance of transmission. Infected individuals recover at a 0.5 rate:
# Creating a SIR model
sir <- ModelSIR(
name = "COVID-19",
prevalence = .01,
transmission_rate = .5,
recovery = .5
) |>
# Adding a Small world population
agents_smallworld(n = 500, k = 10, d = FALSE, p = .01) |>
# Running the model for 50 days
run(ndays = 50, seed = 1912)
#> _________________________________________________________________________
#> |Running the model...
#> |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| done.
#> | done.# Transmission network
net <- get_transmissions(sir)
# Plotting
library(epiworldR)
library(netplot)
#> Loading required package: gridx <- igraph::graph_from_edgelist(
as.matrix(net[,2:3]) + 1
)
nplot(x, edge.curvature = 0, edge.color = "gray", skip.vertex=TRUE)
epiworldR supports running multiple simulations using the
run_multiple function. The following code simulates 50 SIR models with
1000 agents each. Each agent is connected to ten other agents. One
percent of the population has the virus, with a 90% chance of
transmission. Infected individuals recover at a 0.1 rate. The results
are saved in a data.frame:
model_sir <- ModelSIRCONN(
name = "COVID-19",
prevalence = 0.01,
n = 1000,
contact_rate = 2,
transmission_rate = 0.9, recovery_rate = 0.1
)
# Generating a saver
saver <- make_saver("total_hist", "reproductive")
# Running and printing
# Notice the use of nthread = 2 to run the simulations in parallel
run_multiple(model_sir, ndays = 100, nsims = 50, saver = saver, nthread = 2)
#> Starting multiple runs (50) using 2 thread(s)
#> _________________________________________________________________________
#> _________________________________________________________________________
#> ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| done.
#> done.# Retrieving the results
ans <- run_multiple_get_results(model_sir)
head(ans$total_hist)
#> sim_num date nviruses state counts
#> 1 1 0 1 Susceptible 990
#> 2 1 0 1 Infected 10
#> 3 1 0 1 Recovered 0
#> 4 1 1 1 Susceptible 977
#> 5 1 1 1 Infected 22
#> 6 1 1 1 Recovered 1head(ans$reproductive)
#> sim_num virus_id virus source source_exposure_date rt
#> 1 1 0 COVID-19 976 9 0
#> 2 1 0 COVID-19 644 9 0
#> 3 1 0 COVID-19 608 9 0
#> 4 1 0 COVID-19 314 9 0
#> 5 1 0 COVID-19 41 9 0
#> 6 1 0 COVID-19 32 9 0plot(ans$reproductive)
-
The virtual INSNA Sunbelt 2023 session can be found here: https://github.com/UofUEpiBio/epiworldR-workshop/tree/sunbelt2023-virtual
-
The in-person INSNA Sunbelt 2023 session can be found here: https://github.com/UofUEpiBio/epiworldR-workshop/tree/sunbetl2023-inperson
If you use epiworldR in your research, please cite it as follows:
citation("epiworldR")
#> To cite epiworldR in publications use:
#>
#> Meyer, Derek and Vega Yon, George (2023). epiworldR: Fast Agent-Based
#> Epi Models. Journal of Open Source Software, 8(90), 5781,
#> https://doi.org/10.21105/joss.05781
#>
#> And the actual R package:
#>
#> Meyer D, Vega Yon G (2024). _epiworldR: Fast Agent-Based Epi Models_.
#> R package version 0.2-1, <https://github.com/UofUEpiBio/epiworldR>.
#>
#> To see these entries in BibTeX format, use 'print(<citation>,
#> bibtex=TRUE)', 'toBibtex(.)', or set
#> 'options(citation.bibtex.max=999)'.Several alternatives to epiworldR exist and provide researchers with a
range of options, each with its own unique features and strengths,
enabling the exploration and analysis of infectious disease dynamics
through agent-based modeling. Below is a manually curated table of
existing alternatives including ABM [@ABM], abmR [@abmR], cystiSim
[@cystiSim], villager [@villager], and RNetLogo [@RNetLogo].
| Package | Multiple Viruses | Multiple Tools | Multiple Runs | Global Actions | Built-In Epi Models | Dependencies | Activity |
|---|---|---|---|---|---|---|---|
| epiworldR | yes | yes | yes | yes | yes |  |
|
| ABM | - | - | - | yes | yes |  |
|
| abmR | - | - | yes | - | - |  |
|
| cystiSim | - | yes | yes | - | - |  |
|
| villager | - | - | - | yes | - |  |
|
| RNetLogo | - | yes | yes | yes | - |  |
You may want to check out other R packages for agent-based modeling:
ABM,
abmR,
cystiSim,
villager, and
RNetLogo.
Please note that the epiworldR project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.