Data centre and notes

The context in which these data are being collected and documented is unique. We are attempting to track in as timely a manner as possible an unfolding epidemic in which information is limited. Australia's federal system means separate jurisdictions take responsibility for healthcare and report it in different ways. At times, discretion and adaptation have been required. We've tried to document these below.

 

We are grateful to collaborators and especially readers for the many pieces of feedback and advice that have helped with information and decision-making. If you would like to send a comment or request, please get in touch.

 

Index
 

  1. Sources

  2. Data downloads

  3. Per capita calculations

  4. New daily cases versus net daily cases

  5. True daily cases

  6. Confirmed cases and deaths

  7. Calculating rolling averages

  8. Active cases and recoveries

  9. Transmission sources

  10. Cases detected inside and outside hotel quarantine

  11. Testing

  12. Hospitalisations

  13. Clusters

 

Data downloads

You can download our underlying data in the following ways:

  • Most charts have an icon in the bottom left-hand corner that allows you to download a CSV file.

  • Matt Bolton compiles and uploads our key datasets at his github repository: 

    • Confimed cases

    • Deaths

    • Tests

    • Positive Tests

    • Recovered

    • Hospitalised

    • ICU beds

    • Ventilators

  • David Barry uploads transmission sources data (which he provides to this site) at his github respository.

  • View our working spreadsheet tracking COVID-19 deaths in Australia.

 

Please drop us a line to let us know when and how you use the data.

 

Per capita calculations

Per capita calculations use population data as of 31 March 2020. Source: ABS. (Note this is updated as the ABS releases new population data. Previous data were September 2019, December 2019).

 
 

New daily cases vs net daily cases

[Data downloads available]

Summary: The number of new cases each day may differ from the net number of cases added to the total. The Daily briefing on the homepage shows new cases and net added cases in brackets. e.g. 7(+4) = 7 new cases, but only 4 added to the total because 3 previous cases were removed. Epicurves on the site primarily new cases, or in the case of Victoria, official data based on case notifications (which revise daily case numbers to remove duplicates). For the net case epicurves, use the links below.

Several scenarios have led this site to track new daily cases and net daily cases separately. For example, cases are occasionally moved between jurisdictions to comply with national reporting standards that require reporting based on residency rather than locality. This causes cumulative totals to be adjusted upwards or downwards depending on whether the state or territory is sending or receiving the case/s. (In the past, they did not always announce these types of cases explicitly; they simply made adjustments to the running totals). Downward adjustments may also occur after cases have been ruled out following further investigation or false positive results. During Victoria's second wave, the state removed many cases each day due to 'duplicates'. Another scenario that is increasingly frequent is the confirmation of 'historical' cases following serology testing. This is slightly different from the other situations because these cases do still represent new additions to Australia's case numbers, however they are not 'new' cases in an active sense. 

To help make sense of these daily announcements and adjustments, this site tracks new daily cases and net daily cases separately. The goal is to make sure we can see how many new 'active' cases there are, separately from historical cases or technical adjustments.

Other sites tracking COVID-19 cases in Australia usually track net cases added. i.e. Daily cases are calculated by subtracting yesterday's total from today's. Previously this site took that approach also, however it changed policy with respect to downward adjustments as of 15 April 2020, upward adjustments as of 12 May 2020 and newly confirmed 'historical' cases on 17 May 2020. These changes in policy have resulted in some retrospective changes to the epicurve which have been documented below via the charts that show the difference between new confirmed and net added cases.

While the main epicurve, which is on the homepage and states and territories page, shows new daily confirmed cases that are announced by states and territories, this collection of charts is designed to give the full picture of Australia's daily confirmed cases of COVID-19. Data is updated live and downloadable by clicking the download icon in the bottom left-hand corner of each chart. 

1. New daily confirmed cases (i.e. new confirmed cases as announced)
 
  • View and download national data here.​

  • View and download state and territory data here.

2.  Net daily added cases (i.e. cases added to reach announced total)
 
  • View and download national data here.​

  • View and download state and territory data here.​

 

3. Difference between new confirmed and net added cases
 

(Also shows revisions to the epicurve that come out of the changes in approach). 

  • View and download national data here.​

  • View and download state and territory data here.​

4. Cumulative total of confirmed cases
 
  • View and download national data here.​

  • View and download state and territory data here.​

 

'True daily cases'

 

  • In the section above, we discussed the difference between new and net cases. (A state may announce X new daily cases ("new"), while adding a different number to its cumulative total ("net"). This happens when previous cases are removed (e.g. due to duplication or false positives) or historical cases are added).

  • However, there is a third way of capturing daily case numbers, which is actually the truest reflection of daily cases: official case notification data that come from state dashboards or datasets. This site refers to these as 'true daily cases'.

  • This is relevant for NSW and Victoria - the main states that release official data based on case notification dates that are different from the new or net cases announced. This is especially important for Victoria, which has removed large numbers of duplicate cases each day throughout the second wave.

  • For example, let's say Victoria announces 75 new cases today, and adds 60 cases to its total, because 15 previous cases were duplicates and have been removed. We would record 75 "new" cases and 60 "net" cases for that particular day. However, the official case notification data would not necessarily show either. This is because the official data are revised to remove those 15 duplicate cases from their true dates, which is often scattered across several days. What's more, the official data are dynamic and daily case numbers change retrospectively as duplicates are removed. So even if it shows 75 cases today, that may be revised downward tomorrow or the day after, as duplicate cases are removed. True daily cases are sourced from the Victoria dashboard and NSW datasets.

  • Crucially, these data are revised retrospectively as cases are investigated or reconciled. Therefore, any data showing 'true daily cases' is dynamic.

  • What is the date of case notification? Data NSW responded to an enquiry from this site and said it is date test sample was taken, which was later found to be incorrect. NSW Health Surveillance Reports state Date of notification is 'Laboratory notifies NSW Health of result: This date is provided to NSW Health by the laboratory. Laboratories prioritise notification of positive results to allow prompt public health action.' Victoria DHHS did not respond to enquiries from this site, however it appears to be the date the case was confirmed also.

  • This site generally records data against the date of announcement or publication. To align true daily cases with the rest of the site, they cases are recorded with a date one day later than their official dates.​

  • VICTORIA: To compare Victoria's new, net and true daily cases, view this live spreadsheet. (If you find this useful, we'd love to know).

 

Confirmed cases and deaths

  • Cases and deaths are recorded on the day they are announced or published to the public. This means cases recorded on today's date reflect the previous day's reporting period, except in the case of Tasmania. Tasmania generally reports cases from the current day that evening. That means while Tasmania appears to be the last to report, it is in fact the first. After 13 June 2020 (following 0 active cases in Tasmania), there is generally no official announcement about cases in Tasmania until the federal department of health updates its website at night. This site updates Tasmania's cases with 0 at the end of the reporting day (in conjunction with the last state to report) and if new cases are reported by Tasmania that evening, we will reopen and revise.

  • 2 Queenslanders who died in NSW are reported in Queensland figures.

  • At least 2 overseas tourists (non-residents) who died in Western Australia have been included.

  • 20 March 2020: NSW brought its reporting time forward, creating a lower than usual figure for that day. 

  • 6 April 2020: 1 Northern Territory case was removed due to double-count with NSW. (Action taken 1 May 2020).

  • There are ongoing discrepancies between the cumulative total number of confirmed cases as reported by individual states and territories compared with those reported by the federal government. This site currently reconciles with federal figures. The current and ongoing discrepancies in confirmed cases are:

    • Tasmania reports -2 (due to residency)

    • NSW reports -189 (historic cases reported in crew members on board the Ruby Prince cruise ship. They were included on 3 July and for time series purposes assigned to 15 April. NSW Health did not add these cases to its reported total, issuing the following statement in a media release: 189 historic COVID-19 cases reported in crew members on board the Ruby Princess were reclassified as Australian cases and included in NSW totals reported by the Commonwealth Department of Health. These cases were reported as Australian cases to the World Health Organisation as part of the Australian Government’s international reporting obligations. The cases were reported by NSW Health at the time of diagnosis, but were not included in NSW totals as they were on board the ship and not in NSW when diagnosed. The cases were not associated with any further transmissions in Australia as they were managed on board the cruise ship. 

    • The Northern Territory reports +1 compared with federal figures (due to residency). (On 10 November 2020, federal figures added +1 case to the NT, which the Territory did not add, bringing the federal total temporarily into line with that reported by NT. Federal figures failed to add a new NT case two days later, restoring the +1 difference. On 28 October 2020, NT added an overseas-acquired case to its cumulative total, citing the case as an interstate resident. This case was not added to the NT total reported by federal authorities, however appeared to be added on 30 October when the federally reported NT total increased by +1. This site reconciled with federal figures by adding the case retrospectively to NT's new cases dated 28 October 2020).

  • There are ongoing discrepancies between the deaths as reported by individual states and territories compared with those reported by the federal government. This site currently reconciles with federal figures. The current and ongoing discrepancies in deaths are:

    • NSW reports +2 deaths​ (this includes: 1) 1 death of a Queenslander who died in NSW that is counted by both states; 2) An 85-year-old man who died on April 27. His death was not initially classified as COVID-19-related. On 25 June 2020, NSW Health announced that his death had been reclassified as COVID-19 related, following new national guidance on the classification of deaths. This death was added to the NSW death toll, but it was not added to the  national tally. 

  • Running totals of confirmed cases may be adjusted upwards or downwards outside of announced confirmed cases. Please see the section above (new daily cases vs net daily cases) for details.

  • Interstate transfers: where a state announces 'new' cases but verbally specifies that some are 'old' due to interstate transfers, the old cases will not be added to the 'new' epicurve, but added only to the net daily additional cases. 

  • Historical cases following serology testing: Some states have intermittently announced historical cases following serology testing. Western Australia was the only state do so consistently. This site dealt with those announcements by adding these cases as 'net' cases to the cumulative total, but not as 'new' cases. On 1 August 2020, Western Australia made the following announcement: "WA is changing the way cases of COVID-19 are reported, bringing WA reporting closer into line with other Australian jurisdictions. Historical cases will be removed from the State total, meaning the total case count will decrease." A total of 28 historical cases were removed from the total. This website incorporated this change on 9 August 2020, (after both the federal and state dashboards accurately reflected the reduced cumulative totals). Due to the fact that these historical cases had been recorded separately as upward adjustments to the net totals, and not new cases, this site was able to remove these cases from the actual days on which they were announced, preserving the epicurve. If you would like a record of the historical cases that were removed, please contact us. Note that this affected WA recoveries also. When the state announced a historical case, it immediately called it 'recovered'. Therefore, these cases have were removed as recoveries from the correct days on the epicurve. 

  • 18 May 2020: The federal government added +3 net cases for both Victoria and Western Australia in order to reconcile cumulative totals. The originating dates of these cases are not clear, but based on previous downward adjustments that had caused the totals reported by the federal government to diverge from those reported by the states, the cases are likely to be: +2 on 12 May and +1 on 14 May for Victoria:, and +2 on 13 May and +1 on 16 May for Western Australia. Cases that had previously been removed from the net cases on these days have been reinstated.

  • 23 May 2020: Federal figures released by the Department of Health did not add new cases to Western Australia (+3) or Queensland (+2), leading to a total national figure of -5. This site generally reconciles with federal figures at the end of each day. Today however, federal figures are irreconcilable with remaining active cases in Western Australia and Queensland. Therefore this site currently reflects the totals as reported by the states, rather than the federal government. 

  • On 7 August 2020, QLD announced a downward revision of 1 case; however this case was reinstated the following day. The downward revision was removed. 

  • 4 September 2020: Tasmania announced +1 historical case, which was not added to the national toll. (Source).

  • Duplicate deaths in Victoria: Victoria has added net x-1 deaths on 4 occasions, without updating the age and gender of the removed (duplicate) death. This means the age / gender count on this site exceeds the total death toll by 4. The relevant dates are:

    • 10 August 2020: DHHS announced there were 19 new deaths, net +18 added to toll due to a duplication from the previous day. (Noted in press release). Date removed from one line item in order to remove the count of 1 death from 9 August. 

    • 11 August 2020: DHHS announced there were 19 new deaths, net +18 added to toll due to a duplication from the previous day. (Noted in press release). Date removed from one line item in order to remove the count of 1 death from 10 August.

    • 28 August 2020: The Premier announced there were 12 new deaths, but net +11 added to the toll. (Not noted in press release). Date removed from one line item in order to remove the count of 1 death from 27 August.

    • 29 August 2020: The Premier announced there were 18 new deaths, net +17 added to toll. (Not noted in press release). Date removed from one line item in order to remove the count of 1 death from 28 August.

    • 20 September 2020: DHHS announced there were 5 new deaths, net +4 added to toll due to a duplication from a previous day. The day was not specified. The gender / age of this duplicate was not announced or confirmed. Date removed from one line item on 19 September in order to remove the count of 1 death. Awaiting confirmation of details.

  • Delayed notifications of deaths in Victoria: Victoria's DHHS has said the strengthening of national reporting requirements relating to deaths in aged care facilities has resulted in delayed notifications of COVID-19-related deaths. This means that on several days, the new number of deaths (i.e. notified the previous day) differs from the net number added to the total. DHHS has not released information about actual dates of delayed deaths. Therefore, they have been added to the toll on the dates they were announced. To see the specific dates and announcements, see the data notes column in the live working spreadsheet

 

Calculating rolling averages

 

  • In the sections above, we discussed the difference new versus net cases and true daily cases.

  • Different sites may calculate moving averages using any of these inputs.

  • This site prefers to use the last of these as they give the truest indication of daily case numbers (and it is also what Victoria DHHS uses for its roadmap triggers).

  • As discussed, using true daily cases means retrospectively incorporating changes to data - especially the removal of duplicates, as is the case in Victoria.

  • True daily cases are not known until the dashboards / datasets are updated. Therefore this site first updates Victoria's 7-day and 14-day statewide averages using the gross new number of cases announced. It then adjusts this average late in the day when the dashboard publishes the true daily cases. This is preferable to updating with net cases in the meantime, as that would require another adjustment.

  • However is not possible to use true daily cases when calculating averages of metro and regional Victoria as we do not have data of the metro / regional breakdowns of true daily cases; we only know the net cases added to the cumulative totals. Therefore we are limited to recording Victoria's metro and regional averages as announced by DHHS, rather than tracking them independently. 

  • As well as rolling averages, the Victorian roadmap to recovery hinges on rolling totals of cases from an unknown source (community spread). These data are published on this page. While the 14-day average for total cases is updated daily and reflects the rolling 14 day period up until midnight the previous day, the 14-day period for the source of acquisition data ends 48 hours earlier. DHHS says, "this allows for the case interview to have been conducted and an initial determination to made about the source of acquisition. As each case is further analysed its status may be changed accordingly, particularly from unknown to known source of acquisition. The two day delay means that this report may differ from the data provided as part of the daily data reporting." 

 

Active cases and recoveries

  • Before 5 April 2020, not all states and territories reported recoveries. The federal Department of Health began publishing recoveries on this date which created a jump for some jurisdictions.​​​

  • 5 August 2020: NSW Health stopped updating recoveries. It published "NSW Health has suspended its survey of the recovery status of patients with COVID-19 to focus on the recent increase in community transmission. Therefore, recovery statistics are no longer presented. For further information, visit NSW COVID-19 case statistics." NSW still removes 'inactive cases'. See below.

  • 20 August 2020: Victoria reclassified a large number of cases as recovered / inactive. This is called 'release from isolation'. It takes place following an interview with the patient making sure symptoms have cleared and enough time has lapsed since start of illness. 

  • There are ongoing and inconsistent discrepancies between the number of remaining active cases as reported by the federal authorities and those collectively reported by the state and territories. While this site reconciles with federal figures for overall numbers, it reconciles with states and territories to report how many active cases are in their jurisdiction.    

  • This site reflects state and territory figures with the following adjustments: 

    • As noted above, Tasmania reports -2 confirmed cases compared with federal figures. This site has included these cases in Tasmania's cumulative total (in order to reconcile with federal figures) but to date, has not included them in Tasmania's recoveries or active cases. This is in order to align with the figures Tasmania reports.

    • 2 deaths double-counted by Queensland and NSW (allocated to Queensland by this site and federal Department of Health) are being used by both states to calculate remaining active cases. The jurisdiction in which these people were originally counted as confirmed cases is unclear. This site reports the number of active cases as announced by each state.​

When does an active case become a recovery?

 

The answer varies across states and territories. 

  • The national guidelines for COVID-19 define conditions for release from isolation:

    • For asymptomatic cases, at least 10 days must pass without symptoms since the first positive test sample was taken;

    • For mild cases, at least 10 days must pass since the onset of symptoms, and there must have been no acute symptoms in the last 72 hours; and

    • There are further conditions for people who were hospitalised or will enter high-risk settings such as health care or residential age care facilities.

  • Spokespersons for ACT Health, Queensland Health, SA Health and WA Health all said recoveries are determined by public health officials who assess patient symptoms by interviewing the patient and make a determination based on the national guidelines. The Queensland Health website also refers to cases with a notification date of 30 days or more. A spokesperson for NT Health said a patient must return two consecutive negative test results.

  • NSW Health has published recoveries are assessed three weeks after the onset of illness by interviewing the case: cases reporting no symptoms are considered to have recovered and cases who have not recovered at three weeks are called in the following weeks until recovery. On 11 June 2020, NSW removed 104 active cases and published "Active cases are calculated as: total cases excluding persons recovered and lives lost. Cases that are not recorded as recovered or deceased after six weeks are not included.

  • Victoria DHHS and Tasmania Health have not responded to questions clarifying their processes. However, analysis makes it clear that Victoria allocates cases as 'recovered' approximately 10 days after test sample was taken (see the chart on the recoveries page that compares new cases with recoveries).

Inactive cases versus recoveries

  • Sometimes states classify cases as 'inactive' without formally classifying them as 'recovered', affecting the underlying calculation of cases, recoveries and deaths. I.e. The sum of active cases, recoveries and deaths does not necessarily reconcile with the total number of cases.

  • The reason why this is done is not always clear however:

    • Victoria: 

      • The sum of Victoria's reported recoveries, deaths and active cases did not equal the total number of cases reported by that state.

      • As of 22 May 2020, this site reflected Victoria's reported figures of recoveries and active cases separately despite this discrepancy.  

      • On 31 October 2020, Victoria's Health Minister and CHO announced 67 historical cases that had been allocated inactive but not recovered due to the patients being uncontactable, would be classified recovered if 28 days had passed since official notification and no death had been confirmed.

    • NSW:

      • NSW in particular has removed large numbers of active cases without formally classifying them.

      • On 11 June 2020, NSW removed 104 active cases and published "Active cases are calculated as: total cases excluding persons recovered and lives lost. Cases that are not recorded as recovered or deceased after six weeks are not included

      • On 12 June 2020, NSW removed a further 149 active cases. 

      • On 25 June 2020, NSW removed removed a further 90 active cases.

      • On 25 June 2020, NSW updated its definition of active cases. Previously, the state said cases were considered 'inactive' if the patient had not recovered or deceased after six weeks. NSW Health published 'active cases are locally acquired COVID-19 cases with onset in the last four weeks. This is based on the date the person first developed symptoms.' Why would the patient not have been formally classified as recovered? It appears that NSW assesses patient-reported symptoms in order to establish a formal recovery. It is possible that these patients have not been contacted regarding symptoms, however the timing of their disease indicates the case is no longer active.

      • On 3 July 2020, 189 historic cases reported in crew members on board the Ruby Prince cruise ship were added to the NSW total by the federal government. NSW Health did not add these cases to its reported total. (As noted above, this site reconciled with federal figures, adding the cases to the total). The federal government also added these cases to the recovered totals of NSW. This site currently calls these cases 'inactive' rather than 'recovered' as this shows the recovered figure as last reported by NSW and better reflects the state's approach to classifying cases as removed inactive unless a recovery has been positively determined.  

      • On 5 August 2020, NSW Health stopped updating recoveries. It published "NSW Health has suspended its survey of the recovery status of patients with COVID-19 to focus on the recent increase in community transmission. Therefore, recovery statistics are no longer presented. For further information, visit NSW COVID-19 case statistics." The recovery number shown on this site is the last figure published by NSW Health before it stopped. 

    • Queensland: As of 4 June 2020, the sum of Queensland's reported recoveries, deaths and active cases does not equal the total number of cases reported by that state. The state has published ''Active' cases do not equal 'Total' cases less 'Deaths' less 'Recovered' cases, as information for some cases is still pending.' This site reflects Queensland's figures as reported.​​

NSW: Active cases acquired overseas

  • As noted above, NSW no longer includes cases acquired overseas among its official 'active cases' figure. It defines active cases are locally acquired COVID-19 cases with symptom onset in the last 28 days.

  • All other states and territories include overseas-acquired cases among active cases. This creates an inconsistency in reported active case numbers. 

  • Therefore, this site includes an estimate of active cases in NSW that were acquired overseas. Previously, this site did this by calculating the last 14 days of overseas-acquired cases in NSW and adding this number to the official number of active cases. This approach has been modified. Estimates of the number of overseas-acquired active cases in NSW now take the following forms:

    • The table and chart on the NSW page show overseas cases in the last 14, 21 and 28 days. The purpose is to give you an idea of how many additional active cases there would be if overseas-acquired cases were included among NSW actives as they are in other jurisdictions. 

    • For simplicity, the chart on the homepage shows overseas cases in the last 21 days only, however it's recommended that you view the variations on the NSW page as the real period an overseas-case is active is not clear.

    •  In all charts, these are shown separately; not added to the official active total.

    • These figures should be read with caution and taken as logical estimates in the absence of reported data.

 
 

Transmission sources

  • Transmission sources come from a range of sources. NSW, Victoria, Western Australia and ACT provide time series data via data files or dashboards. Every other jurisdiction (including the Commonwealth) reveal transmission sources via press conferences, web pages or updates. There are two main differences between these sources: the date on which transmission sources are announced, and whether they retrospectively update earlier cases that have been reallocated. Daily updates are static representations of cases and transmission sources from which we can only capture what is announced on the day. Time series data are dynamic - they show cases according to notification dates and are updated retrospectively. Data NSW initially advised this site notification dates relate to when the test sample was taken but NSW Health Surveillance Reports state the date of notification is when the 'laboratory notifies NSW Health of result: This date is provided to NSW Health by the laboratory'. Differences between dates of announcements and notification has several impacts:

    • For those states that provide time series data (NSW, Victoria, WA and ACT), the daily announcements of transmission sources are accurate but do not necessarily match the dates in the official datasets.

    • The national view of transmission sources is a static display of cases that shows the developments in the past 24 hours. This includes allocation of new cases (which may or may not have been notified in that 24 hour period) and reallocation of older cases after further investigation. Therefore it will not necessarily show transmission sources on the same dates as the official data from NSW, Victoria, WA or ACT.

    • In general, this site ​reports information on the date it is announced or published, not the date on which a case is notified (which we do not always know). However, for transmission sources, this site now uses different approaches for different charts: 

      • The charts on the homepage are a direct reflection of announcements to the media and public. 

      • The charts on the page Transmission sources: national charts primarily source data from Commonwealth updates and are therefore static and based on announcement date.

      • The charts on the page Transmission sources: state and territory charts primarily source their respective data from the best possible source for that jurisdiction. For NSW, Victoria, WA and ACT, that is their time series data. (Caveat: as previously noted, cases are generally reported on this site against the date they were announced or published to the public, which means cases recorded on today's date refer to yesterday's reporting period. This creates confusion when case-line data (which has no delay) is placed alongside announcement-date data (which has one day's delay). Therefore, an artificial adjustment has been made in which the case-line data has been shifted forward by one day, to synchronise dates with the rest of the charts on this site).

      • Those jurisdictions that do not provide time series data have a different issue - it means that after a case is announced as 'under investigation' it is not often revisited for the sake of clarifying the transmission source to the public. This particularly occurs in Queensland. It affects the charts of daily transmission sources, but it's recommended you view the charts of cumulative totals on the transmission sources: state and territory charts page.

    • Important note re Victoria's transmission sources: As noted above, Victoria published caseline data that showed transmission sources of cases according to their real notification dates, by retrospectively updating the epicurve in the dashboard with information of each individual case's transmission source. On 25 August 2020, Victoria DHHS stopped providing this when it updated to a new dashboard. For 68 days, it provided transmission sources of active cases only, and running tallies of transmission sources once cases were closed. This affected multiple visualisations on this site. Between 25 August 2020 and 31 October 2020, the epicurve showed real caseline data up to 25 August and changes to running totals afterwards. Transmission sources shown by changes to running totals did not tell us the dates cases were notified. This particularly affected cases of community transmission, which are determined after a period of investigation. UPDATE: On 31 October 2020, Victoria reinstated official caseline data showing transmission sources on their true notification dates. All charts and data on this site were retrospectively updated.

  • Charts go back as far as respective available data allow. This varies depending on the jurisdiction.

  • Negative values have been included in some charts to show movement between categories, but large removals of 'under investigation' cases have not always been included.

  • Transmission source updates are limited on weekends due to availability of data.

  • Western Australia ​may allocate a case as 'known local contact' rather than 'overseas acquired', despite the patient having a history of overseas travel and the case being detected while inside hotel quarantine. For example, on 20 September 2020, WA allocated one new case (a 13-year-old male) as 'known local contact', saying he had returned to Perth from overseas, was a close contact of a confirmed case and was in hotel quarantine. ​This site records such cases to accurately reflect the state's allocation method, however these cases are not counted as 'locally acquired' for the purposes of the counter on the states and territories page.

  • ACT: On 11 October 11 2020, federal figures reporting ACT transmission sources showed a move of five cases from interstate to local cases with a known source. This change was reflected in the ACT dashboard at a later date. Data from the ACT dashboard retrospectively adjust cases based on their true dates. The relevant adjustments were made to this site on 4 November 2020.

  • 14 November 2020: Victoria retrospectively moved 515 cases from unknown local source to known local source. Victoria's  Deputy CHO announced this was done after an algorithmic analysis. As this site shows Victoria's true daily cases, these cases were retrospectively revised according to their true notification dates.  

In focus: NSW

  • In the sections above, we have discussed new cases, net cases and true daily cases. When it comes to transmission sources, the NSW page essentially captures all three. Unfortunately while that makes it very accurate and gives you the full picture, it can also be confusing.

  • The three types of daily case data the page show are - 

  1. ​What is announced to the public - shown in the table under 'New today' and in the first chart in the tab 'Last 14 days (new)'. 

  2. Net changes to running totals - shown in the table under 'Net changes'. 

  3. True daily cases from the NSW dataset - shown in the first chart in the last 3 tabs: (Last 14 days (true), Last 3 months (true) and Last 6 months (true).

  • Why capture each one? 

  1. What is announced to the public - this is what people expect to see, based on what they might have read, seen or heard that day. It also captures the message from NSW Health, which is essentially a 'cut to the chase' summary of today's cases.

  2. Net changes to running totals - this was previously not shown on this site because it adds another layer of data that is slightly arbitrary. But the table shows the total number of transmission sources, and therefore it's necessary to show how movements are resulting in the running totals. This is not always the same as the new cases announced to the public. E.g. on 13 October, NSW had +6 new OS-acquired cases, but only 5 added to the total because one was previously removed.

  3. True daily cases from the NSW dataset - this is the most accurate data showing daily cases in NSW. The important thing to understand here is that these data show cases on their notification dates. NSW Health Surveillance Reports state date of notification is when the 'laboratory notifies NSW Health of result: This date is provided to NSW Health by the laboratory'. (Although, we have to add a +1 day delay to this, to make the data align with the rest of the site.) So on the tabs '3 (or 6) months' in the transmission sources chart, if you see transmission sources such as 3 overseas-acquired, 2 known, 1 unknown on 12 October, this means these are the respective transmission sources for confirmed cases the notification dates for which were 12 October (11 October in reality, but delayed by one day on this site for consistency). 

  • What to understand:

  • The first point to understand is notification dates do not necessarily align with announcement dates in a uniform way. Seven new cases announced today might actually come from different notification dates. This means the seven cases will not necessarily be added to today's date. It could be five to today, and two to the day before.

  • The second thing to understand is that the true daily cases represent the official record of transmission sources. Therefore, it does not 'cut to the chase' in the same way announcements in press conferences might. It shows the official status of a case. Very occasionally, these can be quite different. This has occurred on 13/14 October: NSW Health announced several cases as being linked to a known cluster - therefore, we would chalk them up as 'known' - but the original source of this cluster is still not identified, so they were all added to the official record as having an unknown source. In other circumstances, the index case might have had an unknown source, while the others had a known source. But in this instance, NSW Health appears to have put all cases under unknown. 

  • The true daily cases data are retrospectively updated. So when these cases are officially closed, the transmission sources recorded on previous days will change.

  • Further notes on NSW data:

    • Publication of data in the NSW datasets may be delayed - especially on weekends. When this occurs, cases are added as announced and updated with official case notification data when released.

    • 3 June 2020: there were changes made to the NSW dataset which saw cases shift by 1-2 days and some retrospective revisions.

    • 8 June 2020: NSW Health published "the source of 13 previously reported cases has been updated. These cases are known secondary and tertiary infections acquired from people infected overseas who were reported between 24 March and 11 April, and have therefore been reclassified from ‘acquired overseas’ to ‘locally acquired’ as part of ongoing data quality checks."

 
 

Cases detected inside and outside quarantine

  • Charts representing cases detected inside and outside quarantine capture media announcements, through press conferences, media releases and tweets. 

  • Cases detected inside Hotel Quarantine may be explicitly stated, but this is assumed for all cases that were acquired overseas (which is always explicitly stated) since mandatory hotel quarantine commenced.

  • The category of 'Local cases detected inside quarantine / isolation for potential exposure' was added in September 2020, after Queensland and NSW began to give this information at press conferences.

  • NSW Health began including this information in its Weekly Surveillance reports from August 2020. NSW has an explicit definition for these cases: they must have been in isolation for the full 48 hours before symptom onset ('infectious period'); not simply in isolation when diagnosed.

  • Queensland is consistent in its reporting of whether cases were in isolation for potential exposure. NSW and Victoria are less consistent. For this reason, the final category - cases detected outside quarantine or isolation - includes cases whose detection circumstances were not specified.

  • Cases are only included in the category 'Local cases detected inside quarantine / isolation for potential exposure' when explicitly stated. Therefore this category may be under-representative of what has actually occurred, but it will not be over-representative.

  • Hotel Quarantine includes at-sea quarantine. This is particularly relevant for Western Australian cases.

  • To read about active cases inside Hotel Quarantine in NSW, see the section above.

  • Interstate travellers may be included in Hotel Quarantine, especially for Tasmania and South Australia and all states receiving visitors from Victoria.

 

Testing

  • The Federal Department of Health has reported test numbers since 5 April 2020. Previously, data came from state and territory websites, dashboards, media releases and press conferences. Prior to 5 April, not all days were reported / captured for each jurisdiction. 

  • While the Federal Department of Health has reported this metric as 'tests done', it has become progressively clear that testing units have been reportedly inconsistently:

    • On 1 May 2020, Western Australia changed from reporting 'number of individuals tested' to 'number of tests completed'.

    • On 26 May 2020, NSW changed from reporting 'people tested' to 'tests performed' creating a significant rise on that day. The state provides this explanation about the tests that are included.

    • On 27 May 2020, a large jump in Victoria's reported tests indicates a similar change. 

  • There have been instances of bulk removals or additions to testing totals: 

    • ​On 8 June 2020, Victoria removed 12,142 duplicate negative tests.

    • From 20 June 2020, WA has stopped reporting tests on weekends, which creates a larger number reported on Mondays.

    • On 22 June 2020, Queensland reported an additional 38,500 retrospective tests, which were conducted by a private pathology provider.

    • On 10 July 2020, NSW Health reduced the number of tests conducted in NSW by 8,598 from the total after identifying they were interstate tests incorrectly reported through the automated reporting process.

    • On 29 July 2020, SA Health reported a large increase in tests, saying today’s data including an additional private laboratory.

    • From 2 August 2020, Victoria reported rounded estimates of daily tests due to technical constraints. 

    • On 8 August 2020, Victoria removed 11.984 tests from its total. This is possibly to account for rounding errors from the previous week. 

    • On 2 September 2020, Victoria DHHS added  82,309 tests, making a total of 2,331,261 test results have been received by the department since 1 January. This included a data correction of 47,962 tests conducted before 1 August; 17,249 delayed tests from one laboratory; and 17,098 received in the past 24 hours. The Federal Department of Health updated the national testing tally accordingly the following day.​

    • On 19 November 2020, reported tests from SA Health diverged from those reported by Federal Department of Health. This website reconciled with tests reported by SA Health. On 31 December 2020, SA Health reported 5,996 tests but added 4,386 to total. This site initially added the reported daily tests. However, this was later amended on 1/1/20 to add only the net difference of 4,386 in order to reconcile with the the SA Health. This reduced addition also matched the reported total from Federal DOH that day, meaning the two reporting streams reconciled once again.

 

Hospitalisations

  • Data for clusters are collected primarily from Federal Department of Health figures, released either via the Department of Health website or PDF updates from Department of Prime Minister and Cabinet, as well as state and territory dashboards.

    • NSW Health reports out-patients who are receiving care also. This metric is not reported by Federal DOH or any other jurisdiction. NSW Health reports in-patients as a percentage of total patients. This figure is calculated and checked against ​DOH figures each day. 

    • NT does not report hospitalisation figures independently. These figures are only collected via DOH. 

    • In the final months of 2020, Queensland Health's reported hospitalisation figures consistently diverged slightly from those reported by Federal DOH. There appeared to be a one-day delay in the data reported by DOH. Therefore, while this site reconciles hospitalisation figures for all other jurisdictions with federal numbers, we reconcile Queensland's daily figures with those reported by the state. This means the total number of hospitalisations in Australia on a given day may be slightly different from that reported by Federal DOH. Queensland figures account for this difference.

 
 

Clusters

 

  • Data for clusters are collected from health department media releases and press conferences. These announcements do not exhaustively capture known outbreaks and clusters. We record case numbers against the dates of these announcements. Published data are limited to clusters and outbreaks with at least 10 cases.

  • The stream area chart uses the following approach: the start of each cluster is pinned to the first date case/s were announced as part of that cluster or outbreak. The end of the cluster is pinned to the final date new case/s were announced. When no further cases were announced, the cluster is kept open for the next 10 days. Once 10 days pass without any announcements of new cases, the cluster is closed and the final date snaps back to the last day there was a new case announcement. 

  • In some instances, DHHS intermittently released only the number of active cases in a cluster, rather than the total number of cases. When they resumed publishing total cases, this site recorded them on the date of announcement, which is the approach with all figures on this site. These dates however should be read with caution, as they would certainly represent a delay by at least several days since the actual cases were recorded. The relevant clusters are: Bulla Dairy Foods in Colac, Vawdrey Australia Truck Manufacturer, Wydinia Kindergarten in Colac, Peninsula Health Frankston Hospital, Dandenong Police Station.

Data are verified with federal, state and territory health departments. Charts or pages are timestamped with latest updates.

 

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