Public Health England has recently reported that local contact tracing systems—also known as local tracing partnerships—are now in place in over 100 local authorities across England. [1] Seen as one route to help manage rising covid-19 case numbers, these local systems aim to reach cases that the national NHS Test and Trace team is unable to contact.

Source: The BMJ

Reprinted for educational purposes and social benefit, not for profit.

Early results are promising. Blackburn with Darwen, one of the first local authorities to go live at the start of August, reported reaching 9 out of 10 cases that the national system couldn’t get through to. [2] Another local authority to start in August, Calderdale Council, report reaching 86% of cases that otherwise wouldn’t have had their close contacts identified.[1]

However, despite increasing numbers of local systems and promising early results, NHS Test and Trace is still far from the “local by default” system promised by its executive chair, Baroness Dido Harding. [3]

The potential importance of local contact tracing systems can’t be emphasised enough. While NHS Test and Trace generally reaches between 75% and 80% of cases, high case numbers mean that this still left nearly 36,000 cases not contacted in the first two weeks of October. [4] The time taken to reach cases is also increasing. The percentage of cases contacted within 24 hours of being transferred to the national team has fallen from 77% at the start of September to just 54% in early October.

And increasing numbers of cases and contacts that aren’t told to isolate in a timely manner has major implications for breaking the chain of transmission.

Back in May, the government’s Scientific Advisory Group for Emergencies (SAGE) “agreed that at least 80% of contacts of an index case would need to isolate for an effective test and trace system.” [5] In the best case scenario where everyone who had a contact provided their details, in the second week of October, NHS Test and Trace reached 49% of possible contacts (81% of all cases were reached, and 60% of their known contacts). [4]

To compound the challenge faced by NHS Test and Trace, the daily number of official cases is less than half of the number of community cases estimated by the Office for National Statistics. [6] And surveys suggest that as little as 11% of contacts who are notified by contact tracers actually isolate for the required length of time. [7]

It therefore comes as no surprise that in September, SAGE described the current system as “having a marginal impact on transmission at the moment.” [8]

So how can local contact tracing systems help? The model is a partnership between the local authority and NHS Test and Trace. Cases that the national team are unable to reach within 24 hours are passed to the council team. These local teams then try contacting these cases themselves and if successful, pass details about any contacts and potential exposures back into NHS Test and Trace for the national team to follow up.

Some of the cases missed by the national team don’t want to be reached and may never engage. Some will have incorrect contact information and some will have not noticed the call coming through. But others will be more vulnerable, socially isolated, digitally deprived, transient, or economically worse off than cases the national team were able to contact. It’s here where local systems can really make a difference.

The reasons for why local teams are more successful at reaching these cases than the national team are likely to be more than simply being able to draw on local databases to update missing contact details. Having a local phone number appears to help, as does using local call handlers—people who understand their local population and can speak the right languages. Many local authorities also have capacity to visit people at home, further increasing the chance of being able to speak with more vulnerable cases, identify their contacts, and break the chain of transmission.

Local contact tracing systems also place a heavy emphasis on what they can do to help those needing to isolate. This includes providing financial support, social support, and help with accessing essential items like food or medicines—building on local authorities’ experiences of supporting people who were shielding early in the pandemic. And this type of support is known to help improve compliance with isolation. [7,8]

As more local contact tracing systems are launched, their operational models will vary. Some will offer five-day services, others will operate seven days a week. Some will include door-knocking, others will just use call handlers. The variation will be driven entirely by the availability of local resources to staff the system, and the amount of time and capacity available to carry out the necessary steps to get set-up. While support and guidance is provided by Public Health England to help the process, the local effort required shouldn’t be belittled—legal, governance, public health, environmental health, customer services, communications, and finance will all be involved. And this is in addition to everything else they’re currently grappling with, with potential implications for inequalities between local authorities that have differing levels of capacity.

While local contact tracing systems are an appealing additional tool for local authorities managing rising case numbers, it’s getting harder for them to cope. Case rates are going up while NHS Test and Trace performance is declining—this means not only are there more cases, but a greater proportion are being passed on to local authority teams. The weekly NHS Test and Trace data reporting doesn’t separate cases managed by local contact tracing systems from those handled nationally, so we don’t know the impact of this rise in cases on local contact tracing performance.

Most local systems are initially operating based on their share of the £300m allocated for developing and implementing local outbreak control plans in June. [9] Additional money of up to £8 per head of population is now available to councils for enforcement and enhanced contact tracing as areas move into higher levels of restrictions. [10] But lower levels of funding for areas in lower levels of restrictions risks only adequately resourcing these systems after it’s too late.

If contact tracing is going to have more than a marginal impact on viral transmission in England, then the experience of local systems suggests that “local by default” is likely to help. And while there will always be a role for a national system to coordinate processes, training, and technology, as well as managing more routine cases, increasing numbers of local systems are coming online and the remit of more established systems could be expanded. For example, in addition to managing cases, local systems could have a role in following up contacts where just 60% are currently reached by the national system. [4]

But for many local systems, just staying abreast of ever-increasing case numbers will become difficult without additional resources or a mechanism to transfer existing resources from NHS Test and Trace into local government. Until this happens, local systems will help but their impact is likely to remain marginal.

Adam Briggs, Senior Policy Fellow, The Health Foundation, London, UK and Honorary Associate Professor, Warwick Medical School, University of Warwick, Coventry, UK

Competing interests: Alongside his role at the Health Foundation, ADMB is a Consultant in Public Health at Oxfordshire County Council with responsibility for their local contact tracing system.

References:

1 How local tracing partnerships are supporting NHS Test and Trace – Public health matters. https://publichealthmatters.blog.gov.uk/2020/10/19/how-local-tracing-partnerships-are-supporting-nhs-test-and-trace/ (accessed 21 Oct 2020).

2 Health chief says local tracing in Blackburn finds 9/10 people the national scheme couldn’t track – Manchester Evening News. https://www.manchestereveningnews.co.uk/news/uk-news/health-chief-says-local-tracing-18737956 (accessed 21 Oct 2020).

3 NHS Test and Trace service to strengthen regional contact tracing – GOV.UK. https://www.gov.uk/government/news/nhs-test-and-trace-service-to-strengthen-regional-contact-tracing (accessed 21 Oct 2020).

4 NHS Test and Trace (England) and coronavirus testing (UK) statistics: 8 October to 14 October – GOV.UK. https://www.gov.uk/government/publications/nhs-test-and-trace-england-and-coronavirus-testing-uk-statistics-8-october-to-14-october (accessed 22 Oct 2020).

5 Scientific Advisory Group for Emergencies. SAGE 32 minutes: Coronavirus (COVID-19) response, 1 May 2020. London: 2020.

6 Coronavirus (COVID-19) Infection Survey pilot – Office for National Statistics. https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/16october2020 (accessed 21 Oct 2020).

7 Smith LE, Potts HWW, Amlot R, et al. Adherence to the test, trace and isolate system: results from a time series of 21 nationally representative surveys in the UK (the COVID-19 Rapid Survey of Adherence to Interventions and Responses [CORSAIR] study). medRxiv 2020;:2020.09.15.20191957. doi:10.1101/2020.09.15.20191957

8 Scientific Advisory Group for Emergencies. Summary of the effectiveness and harms of different non-pharmaceutical interventions. London: 2020. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/925854/S0769_Summary_of_effectiveness_and_harms_of_NPIs.pdf

9 Local authorities across England receive funding to support new Test and Trace service – GOV.UK. https://www.gov.uk/government/news/local-authorities-across-england-receive-funding-to-support-new-test-and-trace-service (accessed 21 Oct 2020).

10 Covid: How much money are tier 3 areas getting? – BBC News. https://www.bbc.co.uk/news/54630551 (accessed 23 Oct 2020).