How England’s Covid-19 test and trace system is collapsing

The latest data suggests the system is being overwhelmed by the rising number of cases. 

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England’s test, track and trace system was heralded as “world-beating” by Boris Johnson in May – but, after taking months to develop, it has suffered multiple blunders and bottlenecks, and could now have failed completely.

Minutes from the Scientific Advisory Group for Emergencies (Sage) meeting in September contained a stark warning for the government, observing: “The relatively low levels of engagement with the system (comparing ONS incidence estimates with NHS test and trace numbers) coupled with testing delays and likely poor rates of adherence with self-isolation suggests that this system is having a marginal impact on transmission at the moment.”

Since then, the situation has only worsened. The most recent ONS pilot survey estimates 336,500 people in England had Covid-19 in the week to 8 October. This compares to NHS test and trace figures showing 89,874 people tested positive in the week to 7 October. This would mean nearly three-quarters of infected people are not entering the testing system. 

James Naismith, who is director of the Rosalind Franklin Institute and a professor at the University of Oxford, said: “Simply looking at the increase in the number of cases is proof that the system has not succeeded. The reasons are not hard to see. ONS and REACT data suggest testing is missing a significant number of infected people. Those who we do not know about, we cannot trace.”

 

 

The Sage minutes in September continued: “Unless the system grows at the same rate as the epidemic, and support is given to people to enable them to adhere to self-isolation, it is likely that the impact of test, trace and isolate will further decline in the future.”

Statistics show the number of tests carried out in the UK has not risen by the same degree as cases. Meanwhile, the country's case-positivity rate continues to rise. The World Health Organisation has said that a rate of under 5 per cent is a sign that the virus is under control, but the UK has surpassed that level – indicating the testing system is struggling to cope.

 

 

One disease modeller told the New Statesman: “Test and trace is like a fire-beater: great against small grass fires, very much less effective once the whole forest is aflame. So, you might usefully consider where we currently stand in terms of clearly defined outbreaks versus cases just popping up all over a community, instead of low versus high prevalence, although these can be linked.

“If you use this framework to consider the pandemic, it is then reasonably easy to see which of these scenarios we currently find ourselves in, and then to draw conclusions about the likely effectiveness of test and trace.”

[see also: Are pubs and restaurants to blame for the second wave of Covid-19?]

Testing isn’t the only – or indeed the main – issue with the system. Figures released on Thursday 15 October for the latest week of NHS test and trace in England suggest the system is in deep trouble and overwhelmed by the rising number of cases.

Some 62 per cent of identified close contacts were followed up with and told to self-isolate in the week to 7 October – the lowest level recorded since the system was established.

In the last few weeks there has also been a drop in the percentage of contacts being traced within 24 hours – meaning any infected person could transmit the virus over days without being aware they had contracted it. In the week to 7 October, less than 39 per cent of close contacts in non-complex cases who were reached were informed within 24 hours of the case being entered into the system. 

Naismith said: “On average, each person identifies three close contacts, two of which they live with. We have no idea if this is accurate or not, since no effort has been made to find out. The point here is that this is the whole gain of the system – the non-household contacts.

“The Royal Society emphasised speed, but the system is still too slow, with only 60 per cent of close contacts being reached in 24 hours [since identification].”

 

 

And even if people are contacted and told to self-isolate, it is not clear that they will. A pre-print study from researchers at King’s College London and University College London, released last month, found that between March and August 18 per cent of people with Covid-19 symptoms reported that they had self-isolated, while only 12 per cent said they had requested a test. Worse still, only 11 per cent of those who said they’d been alerted by the NHS contact tracing that they had been in close contact with a confirmed Covid-19 case admitted they had stayed at home or quarantined for 14 days.

Naismith added: “I very much doubt the system can recover and run effectively in a timely manner. It will be almost impossible to fix it with cases rising. More likely it will become increasingly irrelevant, but unfortunately increasingly costly.

Even if cases were lower, it is not clear we have learned enough to even know how to make an effective system. The system is a perfect example of, ‘it sounds simple, surely anyone can do it’. Getting a useful system was always incredibly hard. It needed relentless political focus and the right sort of expertise. Even then, it might have failed given the time pressure. Without [focus and expertise] it was certainly going to fail. I fear we delude ourselves by promising hard work or new faces will solve it.”

[see also: The missing data debacle exposes a fundamental problem in the government’s testing strategy]

Michael Goodier is a data journalist at New Statesman Media Group

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