Test, Trace, Protect (contact tracing for coronavirus (COVID-19)): up to 19 December 2020
Management information update on contact tracing delivered as part of the Test, Trace, Protect strategy in Wales up to 19 December 2020.
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In this page
1. What is contact tracing?
Contact tracing is an important part of the Welsh Government’s Test, Trace, Protect strategy. The strategy is being delivered through the NHS Wales Test, Trace, Protect service.
As soon as people start to display symptoms of coronavirus (COVID-19), they should arrange to take a test as quickly as possible whilst they and members of their household self-isolate. Contact tracing is reliant on tests being taken quickly. On receiving a positive result people are asked to support the NHS Wales Test, Trace, Protect service by reporting their recent contacts to the local contact tracer so that they can be contacted and notified to self-isolate (and take a test if they too are displaying symptoms), to help stop the spread of the virus.
It may not be possible to trace all individuals referred to the contact tracing service. For various reasons contact details will not have been provided for some individuals and others may not have responded to calls, texts or emails from tracing teams. The proportion of positive cases that were eligible for follow-up that were reached only include those cases that were successfully reached but does not include those cases where local tracers have made an attempt to contact.
For cases in halls of residence, students may have been contacted by text or by their university to advise them to isolate and not by the local contact tracing team. This type of activity is not captured in the contact tracing data.
The data in this release is management information collected as part of the contact tracing process. The figures reflect the data recorded in the contact tracing system and not any contact tracing activity that may have taken place outside of the typical tracing process. The data has not been collected for official statistics purposes which means it has not undergone the same level of quality assurance as official statistics and will be subject to future revisions. We are publishing this to provide a weekly summary of contact tracing activity in Wales during the coronavirus (COVID-19) pandemic.
2. Main results
Between 13 and 19 December 2020:
- of the 18,128 positive cases that were eligible for follow-up, 14,966 (83%) were reached and asked to provide details of their recent contacts
- of the 33,498 close contacts that were eligible for follow-up, 28,853 (86%) were successfully contacted and advised accordingly, or had their case otherwise resolved
In total, since 21 June 2020:
- of the 97,075 positive cases that were eligible for follow-up, 92,762 (96%) were reached and asked to provide details of their recent contacts
- of the 256,405 close contacts that were eligible for follow-up, 235,892 (92%) were successfully contacted and advised accordingly, or had their case otherwise resolved
| Latest week 13 to 19 December 2020 | Cumulative total 21 June to 19 December 2020 | |
|---|---|---|
| Eligible for follow-up by local contract tracing teams | 18,128 | 97,075 |
| Not eligible for follow-up by local contact tracing teams | 1,725 | 14,942 |
| Total | 19,853 | 112,017 |
Source: NHS Wales Informatics Service (NWIS)
Information on the types of cases not eligible for follow-up by local contact tracing teams is provided in the quality and methodology information section.
| Latest week 13 to 19 December 2020 | Cumulative total 21 June to 19 December 2020 | |
|---|---|---|
| Eligible for follow-up by local contract tracing teams | 33,498 | 256,405 |
| Not eligible for follow-up by local contact tracing teams | 605 | 7,546 |
| Total | 34,103 | 263,951 |
Source: NHS Wales Informatics Service (NWIS)
These figures relate to all close contacts identified in the reporting period shown. Some may have been identified by positive cases referred to the contact tracing system prior to the reporting period. The figures may also include some close contacts eligible for follow-up by local contact tracing teams that were identified by positive cases escalated to regional teams for onward management.
Charts 3 and 4 represent the daily number of positive cases and close contacts eligible for follow up. The number of cases eligible for follow-up for recent weeks may change slightly compared to previous releases due to cases being flagged as not eligible following further investigation by contact tracing teams. More details on this process can be found in the quality and methodology information section.
Variation between days reflects difference in demand on the system (for example, number of tests performed) with some days seeing more cases feeding through to contact tracing teams. A peak in positive cases or close contacts can occur as a result of: a backlog of cases from previous days, a large batch of test results being submitted, a new testing site opening or more testing capacity becoming available.
3. Time taken to reach positive cases and close contacts
Between 13 and 19 December 2020
Positive cases
- Of the 18,128 positive cases that were eligible for follow-up, 24% were reached within 24 hours of referral to the contact tracing system. This equates to 29% of those successfully reached being reached within 24 hours.
- 45% of positive cases that were eligible for follow-up were reached within 48 hours. This equates to 54% of those successfully reached being reached within 48 hours.
Close contacts
- Of the 33,498 close contacts that were eligible for follow-up, 55% were reached within 24 hours of being identified by a positive case. This equates to 64% of those successfully reached being reached within 24 hours.
- 69% of close contacts that were eligible for follow-up were reached within 48 hours of being identified by a positive case. This equates to 80% of those successfully reached being reached within 48 hours.
- 9% of close contacts that were eligible for follow-up were reached within 24 hours of the positive case that identified them being referred to the contact tracing system. This equates to 11% of those successfully reached being reached within 24 hours.
- 24% of close contacts that were eligible for follow-up were reached within 48 hours of the positive case that identified them being referred to the contact tracing system. This equates to 28% of those successfully reached being reached within 48 hours.
4. Data for 1 to 21 June 2020
Early reporting, covering the first three weeks of contact tracing in Wales, was based on data reported by local and regional contact tracing teams prior to the introduction of the national digital system.
In Wales, during the period from 1 to 21 June 2020, 1,905 positive cases were referred to local and regional contact tracing teams. This resulted in 2,616 contacts identified for follow-up, of which 2,117 were successfully contacted and advised accordingly.
There will be a small amount of overlap in the reporting from the national digital system and the early reporting provided by local and regional contact tracing teams. For this reason we would not recommend combining figures from the two different reporting streams. Cumulative reporting in this and future versions of this release will focus on data from 21 June 2020.
5. Quality and methodology information
Data source
This data is management information provided to the Welsh Government by the NHS Wales Informatics Service. We are publishing this to provide a weekly summary of contact tracing activity in Wales during the coronavirus (COVID-19) pandemic. This data has not undergone the same level of quality assurance as official statistics and the data may be subject to future revisions.
Data included in this release was extracted from the contact tracing system at 10:00 on 22 December 2020. This extract was taken 3 days after the end of the reporting period in order to capture follow-up activity relating to cases referred towards the end of the reporting period.
Positive cases and close contacts not eligible for follow-up
The majority of cases not eligible for follow-up by local contact tracers occur in closed settings such as hospitals, care homes and prisons. These cases are escalated to regional teams for onward management.
Positive cases and close contacts that are resident outside of Wales are also not eligible for follow-up by local contact tracing teams. Public Health Wales refer these cases to the relevant public health agency for onward tracing. These cases would have been included in the numbers eligible for follow-up in statistical releases prior to the 10 September.
Time taken to reach positive cases and close contacts
For positive cases, the time taken to reach them measures the time between the case being referred to the contact tracing system and them being successfully contacted. For close contacts there are two measures. The first looks at the time between the close contact being identified by a positive case and them being successfully contacted. The second looks at the difference between the positive cases that identified them being referred to the contact tracing system and when the close contact was successfully contacted.
The latter measure for close contacts excludes a small number that could not be linked back to the positive case that identified them.
The date and time that a positive case or close contact was successfully contacted is taken to be the earliest of a number of events captured in the system. These include:
- successful phone call record
- completion of the contact interview
- first daily check-up
- close contacts or other exposures being entered into the contact tracing system (for positive cases only)
- case marked as ‘resolved’
These events have been chosen as they all indicate that a contact tracer has successfully been in touch with the individual. The range of events is necessary because phone call records do not exist for all positive cases and close contacts. This may arise, for example, where multiple cases live in the same household and the information is captured through a single phone call, rather than one for each individual.
Further quality and methodology information
Close contacts ‘otherwise resolved’ covers a small number of instances where the same contact is identified by multiple positive cases concurrently. On these occasions, contact tracing teams will work from a single record relating to that contact and mark the additional records as resolved.
The number of cases referred for contact tracing is different to the number of new cases published by Public Health Wales. These sources of data are not directly comparable due to differences in timing and the level of validation carried out, as cases submitted to the contact tracing system need to be handled manually by contact tracing teams.
From the 21 October 2020, a small localised pilot to assess the potential to use the contact tracing infrastructure and resource to also provide advice to travellers returning from overseas destinations has been running. Through this pilot activity, additional cases are established within the system that are not subject to the same follow up procedures and processes associated with contact tracing. These cases have a very small impact on the figures presented in this release (representing less than 3% of the weekly cases).
National Statistics status
These statistics are not National Statistics. However, as far as has been practicable, they have been collected and validated in accordance with the pillars and principles within the Code of Practice for Statistics. We continue to develop the data collection and quality assurance process to improve the data.
These statistics have been produced quickly in response to developing world events.
Well-being of Future Generations Act
The Well-being of Future Generations Act 2015 is about improving the social, economic, environmental and cultural wellbeing of Wales. The Act puts in place seven wellbeing goals for Wales. These are for a more equal, prosperous, resilient, healthier and globally responsible Wales, with cohesive communities and a vibrant culture and thriving Welsh language. Under section (10)(1) of the Act, the Welsh Ministers must (a) publish indicators ('national indicators') that must be applied for the purpose of measuring progress towards the achievement of the wellbeing goals, and (b) lay a copy of the national indicators before the National Assembly. The 46 national indicators were laid in March 2016.
Information on the indicators, along with narratives for each of the well-being goals and associated technical information is available in the Well-being of Wales report.
Further information on the Well-being of Future Generations (Wales) Act 2015.
The statistics included in this release could also provide supporting narrative to the national indicators and be used by public services boards in relation to their local well-being assessments and local wellbeing plans.
Next update
This is currently a weekly statistical release. It will be published at 09:30 am every Thursday. We will review the frequency in line with changing user need.
The next update for this release will be Thursday 7 January 2021. This will include data for the week ending Saturday 26 December 2020 and the week ending Saturday 2 January 2021.
We want your feedback
We welcome any feedback on any aspect of these statistics which can be provided by email to kas.covid19@gov.wales.
Further information
For information and advice on contact tracing please refer to our Test, trace, protect: coronavirus guidance page.
6. Contact details
Statistician: Alex Fitzpatrick (for queries about the data)
Telephone: 0300 025 9016
Email: kas.covid19@gov.wales
Media: 0300 025 8099
SFR 246/2020