SARS-CoV-2 is a novel virus and we gain new information on its transmission almost daily, with an incredible amount of new research on COVID-19 being published each week. Consequently, as our understanding of COVID-19 changes over time, we aim to respond accordingly and update our predictions.

Here, we detail the major version changes to the reports produced in this website (minor changes, such as typo fixes and small edits to plots and text are not documented here). These major changes represent either a new methodology or new information being presented. We hope the following overview will help users understand the changes implemented throughout the pandemic.

Lastly, as we switch from one version to the next, there is likely to be a small delay in keeping the website up to date. We apologise for the delays.

Version 5 (additional changes to outputs only so same Version): 2020-10-21

  • Outputs now include estimates of active infections (infection prevalence).
  • For countries without deaths, we provide forward scenario projections that consider if importation of new cases occurred. These scenarios use R0 values comparable to countries from the same income strata.
  • Updated data schema (viewable at, which includes these changes.

Version 5: 2020-08-08

  • 2-week random walk to capture mobility independent human behaviour changes after the post lockdown shift and response to additional waves.
  • We now present the effective reproduction number \(R_{eff}\), which incorporates the impact that immunity has on transmission as well as the impact of interventions. Previously we presented the time varying reproductive number, \(R_t\), which does not show the impact of immunity and only represents changes in transmission due to interventions.

Version 4: 2020-06-28

  • Mobility independent change in transmission is now also modelled (alongside mobility dependent transmission) post lockdown to reflect change in people’s behaviour that is not captured by mobility.

Version 3: 2020-06-14

  • Impact of mobility on transmision estimated both pre and post lockdown for each country, allowing mobility and transmission to be able to decouple after lockdowns are relaxed if the data supports this.

Version 2: 2020-05-31

  • Data on mobility from the Google Community Mobility Reports to inform changes in transmission.
  • Estimates of \(R_t\) included in country reports
  • Projections extended to 28 days
  • Impact of countries nearing health system capacity explored
  • Regional overviews provided
  • Surged healthcare capacity explored (2020-06-02)
  • Fix for looking at healthcare capacity being surged (2020-06-09)
  • Scenario projections provided in zipped files and update historically for each of pipelines (2020-06-09)

Version 1: 2020-04-23

  • Initial version released, with reports presenting information on the following:
    • The total number of COVID-19 infections
    • The expected number of deaths within the next 14 days
    • The number of individuals requiring oxygen or mechanical ventilation in the next 14 days
    • The impact of changing their current intervention policy
  • Model outputs available to download from home page