In public health, identifying symptomatic subjects and their subsequent isolation is proposed and used for infectious diseases to slow outbreaks and, in some instances, stop them.
The conceptual nub of the issue is that in the vast majority of cases, an infectious disease is contagious for a short time. During that period, the source of infection (known as the index case) may infect other people (contacts). Therefore, if you stop contact from the index case and their secondary cases (family, acquaintances, colleagues), you will interrupt or disrupt the chain of transmission of the agent.
Cases are only of interest if they are contagious, i.e., producing so-called replication-competent viruses that can be passed on from A to B and so on, which need to be identified and traced, then isolated to prevent onward transmission.
In the explosive phase of an acute respiratory viral epidemic, testing, tracing and isolation are incredibly labour-intensive as cases multiply exponentially to then level out and fall as the contagion curve obeys Farr’s law.
In Lombardy, by the second week in March, public health had given up testing and tracing as the numbers of supposed cases rapidly overwhelmed public health resources. Tracing, you see, needs to be done based on history-taking. It is time-consuming, and the window of contagiousness is sometimes very short, lasting as little as two days.
No problem: enter PCR as a tool for diagnosis. If applied in large numbers in what amounts to mass testing of whole populations, it can quickly tell you who is ‘positive’. No need to use those old rusty tools of clinical investigation and history-taking, considered old fuddy-duddy stuff in this age.
So in a very short time, PCR capacity went from niche testing in a few laboratories to people waving swabs at motorists in drive-ins – the way out of the pandemic and the return to normal was imminent, we were told.
Except, as discussed in the third instalment of our transmission riddles, qualitative PCR (positive/negative) on its own without recourse to clinical history and an estimate of viral burden cannot distinguish between contagious, convalescent and spurious cases, i.e., due to environmental contamination. If you then set arbitrary cut-offs for positivity, as has been done in most U.K. laboratories, you increase the number of ‘cases’ by an unknown factor.
The consequence, apart from the cost of setting up a programme not founded on science and clinical medicine, is the lengthy isolation of those who never came into contact with SARS-CoV-2 or those who are convalescing, regardless of whether they knew they had been infected. Convalescents can still test positive for PCR as the technique is so sensitive that in the presence of an arbitrary cut-off, the test is picking up viral debris, which is of little interest.
So, we have an expensive programme with no clear, evidence-based objectives. The initial budget was £15 billion; by November 2020, this rose to £22bn; by the time the service was halted in February 2022, it cost £37bn. At its height, over 700 U.K. testing sites were open seven days a week, including Christmas and New Year’s Day.
In the digital era – phone technologies were considered the answer – the dreaded ‘pings’ went unanswered; that’s if you downloaded or switched it on in the first place. But yet again, interventions were untried and untested; however, this didn’t stop them from being rolled out at speed.
But at any point, did anyone ask if there is evidence that such an approach that had never been tried before on such a scale worked or, once rolled out, had been evaluated for effectiveness?
Although contact tracing has a clear logic, its effects depend on the characteristics of the organism, how it is transmitted, the duration of the asymptomatic phase before symptoms manifest, the time the agent is transmissible, the size of the outbreak and the behaviour of the population.
By the time contact tracing shut down in February 2022, 16 million cases had been detected in England, whereas the ONS infection survey estimated 67.6 million had tested positive for COVID-19. Therefore, only about one in four ‘cases’ were detected, and of those testing positive, there was no indication of whether they were infectious at the time.
Given the scale of the outbreak and the nature of the SARs-COV-2 agent, it was clear early on that Test and Trace would be an expensive waste of resources. But at the outset, those in power extolled its virtues.
One of the arguments is that Test and Trace was rolled out too late. Early on, Germany was praised for its Test and Trace strategy. Some advisors incorrectly extolled their strategy; however, Germany equally struggled subsequently and ended up gripped by panic. As a result, it was late in coming out of Covid measures in 2022.
The Test and Trace program ignored the basic rules of infectious disease epidemiology leading to massive disruption of society. Models are insufficient evidence to support £37bn of expenditure – lacking evidence, no other area of healthcare would tolerate such waste.
But you don’t need to take our word for it: in October 2021, the House of Commons Committee of Public Accounts, in its Test and Trace update, similarly considered the program a waste of resources.
- “In March this year, we reported NHS Test and Trace Service’s (NHST&T) failure to deliver on its central promise of averting another lockdown.”
- “In addition, most of the testing and contact tracing capacity that NHST&T paid for has not been used, and despite previous commitments to reduce dependency on consultants, it employed more in April 2021 than in December 2020.”
- “NHST&T’s overall goal is to help break the chains of COVID-19 transmission and enable people to return to a more normal way of life, but there have been two national lockdowns since October 2020 and at the time of our evidence session cases were increasing again.”
Despite all the resources thrown at it, Test and Trace did not show one measurable difference in the outcomes of the pandemic – it did not avoid further lockdowns as promised. Instead, the £37 billion could have paid for roughly a million nurses for the year, or a year and a half of social care cost for everyone that needed it. In October 2020, the PM announced £3.7 billion for 40 hospitals in the biggest hospital-building programme in a generation. He could have nearly rebuilt the whole NHS estate with £37bn. We’ll leave you to consider what you may have better spent the money on.
The budget for Test and Trace now seems unthinkable in the face of a deep recession where every penny counts. Effective healthcare is built on solid evidence of what works, not on opinions of what we think might work. The fact it made no measurable difference is now clear.
The questions for U.K. COVID-19 Inquiry are:
- What was the Test and Trace programme’s aim?
- What evidence was the Test and Trace programme built on?
- How was the quality of the evidence assessed?
- What were the metrics for effectiveness? These should not be process measures such as number tested as these do not measure the spread of the agent.
- Why wasn’t the Test and Trace programme terminated after the damming House of Commons report?
- How can the Government prevent such a massive waste of resources on ineffective interventions in the future?
Dr. Carl Heneghan is the Oxford Professor of Evidence Based Medicine and Dr. Tom Jefferson is an epidemiologist based in Rome who works with Professor Heneghan on the Cochrane Collaboration. This article was first published on their Substack page. It is the first in a series of short notes on topics the authors believe should be addressed by the U.K. COVID-19 Inquiry. If readers have suggestions for other topics, please put them in the comments below or email us here.