From an epidemiological line list to informing decisions in real-time

Nowcasting and forecasting of infectious disease dynamics

“We were losing ourselves in details […] all we needed to know is, are the number of cases rising, falling or levelling off?”

Hans Rosling, Liberia, 2014

  • what is the number of cases now?
  • is it rising/falling and by how much?
  • what does this mean for the near future?

Data usually looks like this

Aggregated data can look like this

UKHSA, 2022
Overton et al., PLOS Comp Biol, 2023

Aim of this course:

How can we use data typically collected in an outbreak to answer questions like

  • what is the number of cases now? (nowcasting)
  • is it rising/falling and by how much? (\(R_t\) estimation)
  • what does this mean for the near future (forecasting, covered in the companion course)

in real time.

Approach

Throughout the course we will

  1. use models to simulate data sets in R
    (the generative model of the simulated data)

Approach

Throughout the course we will

  1. apply generative models to simulated data in Stan to
    • learn about the system (conduct inference)
    • make predictions (nowcasting/forecasting)

Approach

Throughout the course we will

  1. build up to nowcasting: estimating what current counts will be once delayed reports arrive

Approach

Throughout the course we will

  1. finish by linking nowcasting and forecasting, bridging into the companion forecasting course

Timeline

This is the nowcasting course (first half of the week, Monday to Wednesday midday):

  • delay distributions and how to estimate them
  • biases in delays: censoring and right truncation
  • using delays to model the data generating process
  • \(R_t\) estimation and the renewal equation
  • nowcasting, and joint estimation of delays and nowcasts
  • linking nowcasting and forecasting (bridge to the forecasting course)

To start the course go to: https://nfidd.github.io/sismid-nowcasting/ and get started on the first session (Delay distributions)

Return to the session