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The Department of Health and Social Care (DHSC) have released statistics on the first week of the NHS Test and Trace Service for England.
This Roundup accompanied an SMC Briefing.
Dr Bharat Pankhania, Senior Clinical Lecturer, University of Exeter Medical School, said:
“The publication of the weekly NHS Test and Trace bulletin is welcomed – transparency and timely reporting of such data is important for reassuring the public as well as gaining trust and compliance form the public. In fact, the whole operation will be a failure if the public do not voluntarily co-operate in both identifying contacts as well as the contacts complying with requests to self-isolate.
“For the test and trace operation to work, it is important for compliance from the case as well as from the contacts of the case. Both must self-isolate and before the contacts stop their self-isolation it is important to ensure they have not become a case.
“There must be a clear and precise set of instructions (e.g. signs and symptoms to look out for and what to do if they are symptomatic) for contacts whilst they are in self-isolation. The test and trace system will be tracing contacts of the contact in some cases too.
“The Test and Trace operation is very centralised and distanced from the local population. In the long term, over the next 6 to 12 months, we expect local and regional flare up of outbreaks and for these there cannot still be in operation a distant and centralised test and trace system. It will have to be delivered locally by local experts such as the GPs, the Public Health Consultants and their teams, the local Environmental Health officers, the Genito urinary Medicine clinicians and their teams and finally the local expertise from the regional PHE teams. These experts are already in the employment of the NHS, Local Authority or Civil Service. They have expertise in both test and trace, they do this every day and are very experienced at teasing out meticulously the contacts of the case and then advising, informing, and gaining compliance from the contacts. Why they are not a core part of the test and trace operations is baffling – they are involved in identifying, but the operation of tracing contacts is then handed over to the centralised Test and Trace operations rather than also done by the local teams.
“With the 8,117 people who tested positive for coronavirus (COVID-19) between 28th May and 3rd June 2020: 5,407 were cases from whom it was possible to obtain contact tracing information. Thus 33% of cases produced a nil return as far as contacts are concerned. The 33% of cases not being able to provide any contact tracing details is of concern and needs monitoring. In expert hands, where there is no dependence on an algorithm and a script, there would be a better outcome and compliance.
“It is a positive that most cases were contacted and asked to provide information about their contacts within 24 hours. What is not known is the time taken from testing, to results obtained to the test and trace service taking over the contact tracing process. It is important to know about the time taken from testing to results to finally getting to the test and trace operations.
“The 5,407 cases generated 31,794 contacts. It is clear to see that if the case numbers go up, the numbers of contacts will rise exponentially too and eventually the trace system will not be able to cope and deliver on the trace functions. In the early days of this test and trace operations, it is promising to note that 85% of contacts were contacted. Important to monitor and act on the 15% who were unable to be contacted. If this unable-to-contact number continues to rise it will be an indicator of the trace service not managing to remove from circulation a significant number of potential cases-to-be.”
Prof Anne Johnson FMedSci, Professor of Infectious Disease Epidemiology, UCL, (and member of the DELVE committee, who produced a report on TTI for the Royal Society), said:
“The experimental statistics on the Weekly NHS Test and Trace bulletin, England: 28 May – 3 June 2020 are to be welcomed as the first data release from the new national system after its first weeks of operation. As acknowledged by Baroness Harding and Prof John Newton today, there is much more detail required before we understand its overall impact, but given the speed of set up, they have got off to a good start with 8,117 cases put though the system and 26,985 contacts reached and advised to self -isolate. But as in all contact tracing systems there are delays and drop-outs all along the isolate, test and treat pathway. A high fraction of diagnosed cases were input to the system but only 67% reached and provided contacts. Once contacted, there were high levels of compliance with a reassuring 85% saying they will self-isolate.
“But the major benefit of the new system comes as much from the wide availability of testing as from tracing. The greatest impact in reducing transmission, as the Royal Society Delve report showed, comes from people self-isolating and quarantining their families as soon as they develop possible Covid symptoms and then rapidly testing. This means that those who test negative can resume usual activities, while those who are positive can protect their families and contacts and access appropriate care as needed. The effectiveness of contact tracing relies on speed of the whole system from first reporting symptoms, to test result, to tracing of contacts, and on high levels of compliance, and not all these data are yet available. But early signs are that the contact system is acceptable to a high proportion of the population and a majority are reached within 24 hours of a positive result. But there is more work to be done on speeding the system and on data quality and completeness.
“We need more data on all aspects, including regional breakdown and on the substantial proportion of cases and contacts being identified as part of outbreaks by local public health teams alongside the wider community system. But is good news to see that the systems are integrated. In time, more granular data will be needed on epidemiological characteristics, outbreaks and the effectiveness of action taken to contain them. The system will never catch all cases, since many are without symptoms, nor will it be a silver bullet in reducing spread but, alongside social distancing, masks and infection control measures, it is one important strand of the intense work now needed to reduce the ongoing impact of the epidemic.”
Prof James Naismith FRS FRSE FMedSci, Director of the Rosalind Franklin Institute, and University of Oxford, said:
“Tracking and isolating the contacts of infected people has been shown in South Korea to be a very powerful tool in controlling covid19. The goal of such a test, track and isolate system is to keep infection rates low and localised. This would allow people to lead much more normal lives and save lives. If we don’t get this system operational then we face two awful choices, allow the virus to spread unchecked or cycle through lockdowns.
“These new data release illustrates the complexity of a track and trace system; this is not an “easy” thing to do. There are encouraging details in here, particularly the time taken to identify and reach out to contacts. Other areas will need improvement. The goals have to be to have a very short time between a person supplying a sample for testing to their contacts being reached. Secondly, we need to process close to all positive cases. Thirdly, the isolation of infected contacts has to be effective. This system only works if all three components do. In a democracy, such a system needs widespread public support.
“People were asked to identify their contacts – this needs the public’s trust to share such information. Contacts were asked to self isolate – this needs the public’s consent. More thought needs to be given on how to make self isolation easier. We should remember that many contacts will not have been infected, of those who have been infected most will feel completely well. Repeatedly asking people who feel absolutely fine to put their lives on hold is unlikely to be tolerable and in time will erode public support.”
Prof Sheila Bird, former Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:
“First, I congratulate the Test, Trace & Isolate [TTI] team for their prompt publication of key monitoring statistics about the TTI-operation during 28 May to 3 June 2020.
“Second, prompt monitoring leads to improved performance and so we may anticipate further improvements in forthcoming weekly-reports.
“Third, a good start has been made.
“Inevitably, I have some requests for further information to be presented in future reports.
“The good start is as follows. During its first week of operation, 8 117 index cases who had tested positive for SARS-CoV-2 were referred to TTI, two-thirds of whom (5 407) were reached and asked to provide contacts outside of their household (95% CI: 65.4% to 67.9%). Recall that their own household should already be isolated at home in view of the index case’s positive diagnosis.
“For some reason, time from referral to contacting of the index case has been documented for only 4 216 (78%) of the 5 407 index cases who were reached: for 3 336 (79%) of these 4 216 index cases, referral-to-contact time was within 24 hours. But time-intervals are missing for 21% of index cases.
“The close contacts identified numbered 31 794 but it is unclear whether these were nominated by the full set of 5 407 index cases (mean of 5.9 close contacts outside of own household) or by the sub-set of 4 216 index cases (mean of 7.5 close contacts outside of own household). The TTI-team reached 26 985 of these external close contacts (95% CI: 84.5% to 85.3%).
“For some reason, time from identification of close contacts to requesting close contact’s self-isolation appears to be available for only 5 278 (20%) of the external close contacts who were reached, so low a percentage that the distribution of the reported times could be importantly different from that for 26 985 external close-contacts who were reached.
“In summary, referral of 8 117 index cases (1 160 per day versus daily new infections in the community estimated as 5 600) resulted in the 26 985 external close contacts being asked to self-isolate for 14 days from their last contact with their unknown index case. These additional self-isolations requested of external close contacts averaged 3.3 per index case.
“Requests for further information include: explanation of the missing time-intervals; separate accounting for index cases referred to TTI as part of an outbreak investigation rather than because individual index case had booked a test; analysis by sex and age-group of index cases; information upfront on the delays from symptom-onset to test-booked to positive-result to TTI-referral. Finally, we shall want to know: how many of the 3.3 self-isolated external close contacts per index cases were SARS-CoV-2 positive (whether symptomatically or asymptomatically, see below).
“Most importantly, future reports should use random sampling to discover what percentage of external close contacts is swab-test positive at different phases of the self-isolation and, indeed, to check that self-isolation has been adhered to. Finally, information about the number of non-identifiable close contacts per index case is also critical to try to document as such contacts are likely to increase per index case as lockdown eases progressively.”
Prof Keith Neal, Emeritus Professor of the Epidemiology of Infectious Diseases, University of Nottingham, said:
“85% of contacts being reached is a good result, but we don’t know how many will self isolate for 2 weeks. The more that do the better.
“Being unable to contact 33% of diagnosed cases is a concern particularly as a mobile number is involved in requesting the test. Some of these are part of other investigations including those related to care facilities – this data should be obtainable and identifiable. Nearly 80% of those reached were contacted in a timely manner.
“An absolutely crucial part of the test and trace system is the public committing to it – the system can not work without the public’s involvement.”
Prof Mark Harris, Professor of Virology, University of Leeds, said:
“It is gratifying to see that finally contact tracing is up and running. As has been mentioned many times over the past 3 months, this is one of the key ways in which we will overcome this pandemic.
“If the system is to be effective it has to work efficiently and quickly – the statistics show that of those positive individuals who could be reached, 79% were contacted within 24 hours. Subsequently 85% of identified contacts were reached within 24 hours. These stats are encouraging but of course there is room for improvement – in particular only 67% of positive individuals could be reached for a number of operational reasons (e.g. wrong contact details).
“However, what is both surprising and concerning is that the contacts identified are only being asked to self-isolate for 2 weeks. Why are they not being tested, as is undertaken in other countries? By testing contacts we will also be able to identify other infected individuals and broaden the scope of the contact tracing to the next tier of contacts. This will help in identifying potential foci of infection and possibly inform localised lockdown strategies. We have the capability to test these contacts – as we have heard in many Government press conferences the facilities for large scale testing are now operational. It is clear however that some of these facilities are working well below capacity due to a lack of samples – this disconnect needs to be addressed urgently.”
https://www.gov.uk/government/statistics/nhs-test-and-trace-statistics-england-28-may-to-3-june-2020
All our previous output on this subject can be seen at this weblink:
www.sciencemediacentre.org/tag/covid-19
Declared interests
None received.