PHE statement on delayed reporting of COVID-19 cases
A technical issue, now resolved, resulted in cases between 25 September and 2 October not being included in the reported daily COVID-19 figures.
Interim Chief Executive, PHE, Michael Brodie said:
A technical issue was identified overnight on Friday 2 October in the data load process that transfers COVID-19 positive lab results into reporting dashboards. After rapid investigation, we have identified that 15,841 cases between 25 September and 2 October were not included in the reported daily COVID-19 cases. The majority of these cases occurred in most recent days.
Every one of these cases received their COVID-19 test result as normal and all those who tested positive were advised to self-isolate.
NHS Test and Trace and PHE have worked to quickly resolve the issue and transferred all outstanding cases immediately into the NHS Test and Trace contact tracing system and I would like to thank contact tracing and health protection colleagues for their additional efforts over the weekend.
We fully understand the concern this may cause and further robust measures have been put in place as a result.
Test and Trace and PHE Joint Medical Advisor Susan Hopkins, said:
Our analysis now shows that this issue affected a total of 15,841 cases from the period between 25 September and 2 October, with the majority occurring in recent days. This means the total number of positive cases over this period was higher than previously reported.
Of these, over 75% (11,968) relate to cases that should have been reported between 30 September and 2 October.
This issue did not affect people receiving their COVID-19 test results and all people who tested positive have received their COVID-19 test result in the normal way. It also does not impact the basis on which decisions about local action were taken last week.
All outstanding cases were immediately transferred to the contact tracing system by 1am on 3 October and a thorough public health risk assessment was undertaken to ensure outstanding cases were prioritised for contact tracing effectively.
The advice remains the same. If you have tested positive you must self-isolate immediately for at least 10 days from when your symptoms began and we urge everyone who is contacted by NHS Test and Trace to provide details of their recent contacts.
Background information
Due to a technical issue, which has now been resolved, in the automated process that transfers COVID-19 positive lab results into reporting dashboards and for contact tracing, 15,841 cases between 25 September and 2 October were not included in the reported daily COVID-19 cases. The majority of these cases (11,968, over 75%) occurred in most recent days.
This issue has not affected people receiving their COVID-19 test results - all people who tested positive have received their COVID-19 test result in the normal way. This also has no impact on app users.
All outstanding cases were immediately transferred to the contact tracing system by 1am on 3 October and a thorough public health risk assessment was undertaken to ensure outstanding cases were prioritised for contact tracing effectively. NHS Test and Trace have made sure that there are more than enough contact tracers working and are working with local Health Protection Teams to ensure they also have sufficient resources to be urgently able to contact all cases. We are also increasing the number of call attempts from 10 to 15 over 96 hours.
The technical issue was caused by the fact that some files containing positive test results exceeded the maximum file size that takes these data files and loads then into central systems. A rapid mitigation has been put in place that splits large files and a full end to end review of all systems has also been instigated to mitigate the risk of this happening again. There are already a number of automated and manual checks that happen throughout.
The JBC and PHE have confirmed that this would not have impacted the evidence base on which decisions about local action were taken this week, as the majority of people would not have tested positive at that stage. The increase in cases are spread proportionally across the country as per the current levels of the virus.
The dashboard on GOV.UK has now been updated and the correct number of cases by specimen date is shown in the cases section. Today and yesterday’s headline number are large due to the backlog of cases flowing through the total reporting process.
The delayed reporting are all positive cases identified via Pillar 2 testing between 24 September and 1 October.
| Date (recorded – flow though into following day’s published numbers) | Expected reported date for GOV.UK | Cases that were not included on the expected data |
|---|---|---|
| 24/09/2020 | 25/09/2020 | 957 |
| 25/09/2020 | 26/09/2020 | 744 |
| 26/09/2020 | 27/09/2020 | 757 |
| 27/09/2020 | 28/09/2020 | 0 |
| 28/09/2020 | 29/09/2020 | 1415 |
| 29/09/2020 | 30/09/2020 | 3049 |
| 30/09/2020 | 01/10/2020 | 4133 |
| 01/10/2020 | 02/10/2020 | 4786 |
Last updated 5 October 2020 + show all updates
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Added background information.
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First published.