---
title: "Introduction to Rnaught"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Introduction to Rnaught}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

The goal of Rnaught is to provide a a collection of methods for estimating the
[basic reproduction number](
https://en.wikipedia.org/wiki/Basic_reproduction_number) ($R_0$) of infectious
diseases.


## Estimators

The following estimators are currently available: 

  * `id()`: Incidence Decay (ID)
  * `idea()`: Incidence Decay and Exponential Adjustment (IDEA)
  * `seq_bayes()`: Sequential Bayes (seqB)
  * `wp()`: White and Pagano (WP)

Every estimator employs its own model, has its own set of parameters, and is
better suited to particular scenarios. You should consult each method's
documentation for technical details. Below is a short example computing
estimates for a given set of case counts.

```{r}
library(Rnaught)

# Weekly case counts.
cases <- c(1, 4, 10, 5, 3, 4, 19, 3, 3, 14, 4)

# Compute estimates of R0, assuming a serial interval of five days.
mu <- 5 / 7

id(cases, mu)
idea(cases, mu)
seq_bayes(cases, mu)
wp(cases, mu)
```


## Web Application

This serves as a graphical interface for the package. An instance is available
at <https://immune.math.yorku.ca/Rnaught>. It can also be run locally by
invoking the `web()` function.

Datasets can be uploaded as a CSV file, or entered manually. The data is
visualized in the application through plots that show the case counts (either
daily or weekly). If multiple datasets are added, the trends corresponding to
these datasets are populated in the same plot. This plot can be exported as a
PNG image. Furthermore, the datasets entered can be exported as a CSV.

Two sample datasets are included: weekly Canadian COVID-19 case count data from
March 3rd, 2020 to March 31st, 2020, and weekly Ontario COVID-19 case count data
from March 3rd, 2020 to March 31st, 2020.

To estimate the basic reproductive number, the user can choose their preferred
estimator, and if applicable, must enter the known
[serial interval](https://en.wikipedia.org/wiki/Serial_interval) prior to
estimation. If multiple estimates of the basic reproductive number are
calculated, they are all included in a table where each row represents an
estimate. If multiple datasets are being considered, the basic reproduction
number is estimated for all datasets and the columns of the table correspond to
the different datasets. The table also consists of a column corresponding to the
value of the serial interval. This table can also be exported as a CSV.


## Datasets

The package includes two datasets provided by the [COVID-19 Canada Open Data
Working Group](https://github.com/ccodwg/CovidTimelineCanada).
These report the national and provincial case counts of COVID-19 in Canada. For
details, see `?COVIDCanada` and `?COVIDCanadaPT`. They are also available as
[CSV files](https://github.com/MI2YorkU/Rnaught/tree/master/inst/extdata).