Better testing needed for a COVID-19 exit strategy – “data not dates” from Gordon Woo

 

By Gordon Woo for

COVID-19 Actuaries Response Group – Learn. Share. Educate. Influence.

  Covid-arg.com


Summary

Vaccines alone cannot resolve the COVID-19 crisis. We need to follow the virus, not just the disease: this requires a fully functioning NHS Testing and Tracing system (NHSTT) to contain outbreaks. New variants with increased infectiousness have made this more important.

There is reason to hope that a fully functioning NHSTT can be established in 2021. Measures recommended by SAGE behavioural scientists to encourage compliance with isolation and quarantine can be adopted, and technological advances in diagnostic testing can increase the capacity and speed of testing.

Ideally, an instant, accurate and low-cost test is needed for a robust COVID-19 exit strategy. Recent developments in aptamer research offer hope that such a test may arrive this year.


Contact tracing and quarantine compliance

Vaccines provide a welcome route for societal escape from a repeated cycle of pandemic waves, disruptive and costly lockdowns. But however efficiently vaccines are rolled out, vaccine effectiveness is not perfect, some may choose not to be vaccinated (perhaps for medical reasons), and people under-18 are not designated to be vaccinated. The containment of COVID-19 after summer 2021 needs the NHS Testing and Tracing system (NHSTT) to be fully functional, after the understandable technical and logistical challenges of starting from scratch in 2020. Otherwise, according to Prof. Neil Ferguson, there is a prospect of societal disruption until the end of the year[1].

SAGE set a high target of 80% for the proportion of contacts of each infected person who should be traced. At the beginning of September 2020, NHSTT was able to contact around four out of five cases transferred to its system, four out of five provided details of contacts, and three-quarters were subsequently reached[2]. As of mid-November, 85% of people were reached for contact information, but only 73% of their identified contacts were reached, so that the success rate of contact tracing was still only around 60%. In the last week of 2020, when 270,000 people were transferred to the NHS Test and Trace system, 68% provided details of at least one close contact, and 92% of identified contacts were reached. This last higher figure reflects an improvement in managing contacts in the same household. However, the SAGE target is far from being met.

The best opportunity for NHSTT to be properly functional is when it is not being swamped with many thousands of new cases per day. German authorities have reckoned on having five contact tracers per 100,000 citizens[3], with a manageable number of weekly cases for diligent contact tracing being around 50 per 100,000. For the UK population, this would equate to around 5,000 cases per day. The UK Prime Minister told the House of Commons on 20 May 2020 that UK would have a system capable of tracking 10,000 cases per day by 1 June. Even if this had been achieved four months later by the beginning of October, when there were 10,000 new confirmed UK cases per day, it would have indeed been world-beating. With the experience gained and lessons learned from 2020, the SAGE aspirational 80% target for contact tracing should be achievable in the summer of 2021, once the number of new cases is brought down by vaccination to below a few thousand per day.

In the ambitious UK contact tracing plan, non-compliance with quarantine was not adequately addressed. In Taiwan, where there were only 7 COVID-19 deaths in all 2020, 99.7% compliance was encouraged through financial assistance, and achieved through advanced rigorous electronic tracking of cell phone movements. In a King’s College London survey[4], issued on 18 September 2020, only 11% of UK citizens said they would comply with quarantine. Two days after publication of this study, a new UK government package to support and enforce self-isolation was announced. This included a payment of £500 for those on lower incomes, and fines for breaching self-isolation.

These measures became UK law on 28 September 2020, during the emergence of the second wave of COVID-19. This package for support and enforcement of self-isolation was needed, but came too late for containing COVID-19 in the autumn of 2020. However, this package should make a substantial contribution to mitigating the spread of COVID-19 in 2021. SAGE has suggested this support package might be more generous for less affluent households[5].

Another measure, advocated by SAGE, is the facility for those tested positive to isolate away from their households in special quarantine centres or hotels. This would be especially helpful in poorer districts, with high population density and many multi-generational households. 6% of UK households, a total of around 1.8 million people, are multi-generational. One such district at higher risk is the London Borough of Newham, which has 70% BAME population[6]. In the week to 2 January 2021, there were almost 5,000 confirmed cases of COVID-19 in this deprived borough: the highest figure in London. Quarantine centres for those tested positive for COVID-19 have been successfully run in a number of countries, including China and Israel. Sir David King, leader of Independent SAGE, has pointed out the value of quarantine hotels in New York. Such facilities cut household transmission and would contribute to containing the urban spread of the new variant of COVID-19 in 2021, as well as serving to mitigate the excess vulnerability of BAME communities.


Accurate and affordable testing

One of the principal obstacles to effective digital app-based contact tracing is the requirement to self-isolate for ten days from when there was last contact with the person tested positive for COVID-19. It has been suggested that this self-isolation order should hold only until an individual has been tested negative by the public health authority. A UK survey has indicated that 90% of people would likely comply with self-isolation if there were a rapid test available[7]. This contrasts starkly with the 11% figure above from the King’s College survey. For someone with no symptoms to stay at home when they could be earning a living or looking after their family is clearly difficult, and creates a dilemma for them. But with the reproduction number of the new UK variant being materially higher, compliance with self-isolation needs to be raised to 90%. Rapid testing is crucial for this to be achieved.

The general availability of accurate and affordable testing would boost compliance and increase the effectiveness of NHSTT enormously. Consider air travel for example. Instead of the honour system of expecting arrivals to UK to self-isolate for ten days, (which has often been treated as discretionary), as of 15 January 2021 there is a requirement for travellers to UK to have a negative test before departure. Since the discovery of the new more transmissible UK variant, US citizens returning to USA are required to have a test within 72 hours of departure.

This is now perfectly viable in January 2021: an accurate PCR test delivers results in a day and costs £80 at Heathrow. As of 15 February 2021, concern over the spread of the South African and Brazilian variants has led to the introduction of quarantine hotels for many arrivals in UK. Those quarantined will be tested on the second and eighth days of their self-isolation.

Faster and cheaper, but much less able to detect low levels of infection, are lateral flow devices, which can display point-of-care results in 15 to 30 minutes, without the need for laboratory processing. These tests look for protein antigens which live on the surface of a virus. Tests cost between £5 and £20. Lateral flow tests form the basis of the UK government’s “moonshot” programme of mass testing[8], rolled out across England. They are also being accepted for travellers to UK.

During the periods when some UK restaurants were open, subject to social distancing, instant temperature checks were introduced by some COVID-secure establishments. Had one been available, an instant, accurate and low-cost COVID-19 test would have allowed such restaurants to open fairly normally. At a cost of a few pounds per person, many other public venues, including theatres, concert and convention halls and stadiums, might also resume normal function.

On 7 December 2020, the game-changing prospect of an instant, accurate and low-cost COVID-19 test came a little closer to reality with a press release from the Canadian company, Two-Photon Research (TPR). Montreal-based TPR has used its expertise in light sciences, optics and microbiology to develop a radically new solution for virus testing: Aptamer Molecular Photonic Beacon (AMPB)TM. Aptamers are a special class of short nucleic acid molecules that fold into 3-D shapes, capable of binding with high affinity and specificity to a target molecule. TPR’s diagnostics platform works by binding aptamers to the S1 protein in the spikes on the surface of the SARS-CoV-2 molecule. The aptamer’s shape is changed so that it complements a chain of atoms in the S1 protein, rather as a key matches a lock. By changing the AMPB aptamer and finding the right shape, multiple viruses or virus mutations could be detected with a single test.

The AMPB is placed in a 4 ml vial where it will bind with the virus’s S1 protein – if it happens to be present in the saliva sample of the individual being tested. Light emitted by the AMPB is detected by sensors that convert light into electric signals. Such sensors are contained in a smartphone camera and activated via an app. A green icon pop-up on the smartphone screen instantly indicates a negative result; a red icon indicates a positive result. The time and GPS data for the test are stored with the result, and can be communicated electronically to health authorities. The centralisation of test data would be a huge benefit in tracking the spatial-temporal evolution of the virus. A five-vial test kit is estimated to cost around £25, which would make daily testing feasible for many people.

TPR has completed in vitro testing of its technology, and the accuracy has been shown to be as good as a PCR test. In vivo testing is due to begin in January. There is no guarantee that AMPB will be available in 2021; other aptamer-based testing initiatives have missed progress milestones. However, an instant, accurate and low-cost COVID-19 test, whenever it is available, should be part of a robust COVID-19 exit strategy, to complement the mass vaccination programme. Furthermore, as with the new plug-and-play vaccine technology, this new instant diagnostic technology would be a crucial component of future pandemic risk management, and also crucial to the long-term insurability of pandemic risk.

 

16 February 2021


[1] BBC Panorama (2021) 11 January.

[2] Briggs A. et al. (2020) NHS Test and Trace: the journey so far. Health Foundation, 23 September.

[3] BMJ (2020) Lessons in contact tracing from Germany. 25 June.

[4] Smith L.E. et al. (2020) ICORSAIR study, King’s College, London, doi.org/10.1101/2020.15.20191957, 18 September.

[5] Susan Michie, behavioural science team at SAGE. January 2021

[6] Newham London  www.newham.info

[7] Abeler J. et al. (2020) Support for App-based contact tracing of COVID-19. OSF preprint.

[8] Iacobucci G. (2020) COVID-19 government ramps up “Moonshot” mass testing. BMJ, 17 November.

About henry tapper

Founder of the Pension PlayPen,, partner of Stella, father of Olly . I am the Pension Plowman
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