Transmission sources:

national charts

Key concept 
Data about transmission sources come through three avenues: 1) media announcements about gross new daily cases; 2) net additions and changes to running totals on government websites; 3) official data that is tethered to individual cases. Each of these have different points of value and limitations. The charts on the homepage show gross daily cases as announced. The charts below show net additions and changes. For more details, please read the data notes.
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View the chart above since earliest available data or for individual jurisdictions.  
Data note
Mandatory hotel quarantine began on 29 March 2020. The chart below tracks cases in hotels versus those that were locally acquired or under investigation. While a similar chart on the homepage shows the transmission sources of gross new cases as announced at press conferences, the chart below shows net additions and movements . 
Data note
'Community spread' occurs when the epidemiological source of a transmission cannot be identified. It is also known as transmission from an unknown contact. The dates below reflect the days when cases were added to the running totals of community transmissions (usually after a period of investigation).