Before we had vaccines, NHS Test and Trace was supposed to be the breakthrough that would return us to a normal life. After all, testing, tracing and isolating contacts of infected people was credited with keeping Covid infections down in South Korea, Taiwan and elsewhere, so why wouldn’t it work here?
Instead, we had a second wave and the return to normality was reversed. In September, Sage, the government’s scientific advisory committee on emergencies, was dismissive, saying Test and Trace was having only a 'marginal effect’. A report by the National Audit Office in December, by which point the system had already cost taxpayers £22 billion, was equally scathing. At that time, the NAO discovered, the system was only returning 40 per cent of tests within 24 hours.
But what does the Department of Health and Social Care think of its own system? This week it has published an evaluation of the Test and Trace system — or at least of how it was operating last October (it is now estimated to be reaching most ‘close contacts’). Its modelling concludes that it was at that point reducing the R — the theoretical number of people the average Covid infectee goes on to infect — by between 0.3 and 0.6. The R number at the time was estimated to be 1.2.
However, most of this reduction, it estimates, was caused by the testing and isolation of symptomatic individuals alone — that helped reduce the R number by between 16 and 28 per cent. The business of tracing the contacts of those infected people and ordering them to self-isolate had a very small effect, reducing the R number by 2 to 5 per cent.
The initial plan for Test and Trace assumed the system would have a significantly larger effect. In October, the DHSC study concludes, that the contact tracing alone ought to have reduced the R number by between 7 and 10 per cent. As a whole, the Test and Trace system ought to have reduced the R number by between 0.5 and 0.8 in October. Had Test and Trace been operating according to its business plan, the modelling therefore asserts, it ought to have brought the R number down by an additional 0.2 — from 1.2 to around 1.
This is, of course, only modelling. Moreover, not everyone will want to trust an evaluation that has been made by the Department for Health and Social Care, which of course has a vested interest in justifying the decision to splash so many billions on Test and Trace, even while admitting that it wasn’t working as it should have been.
We will never know for sure whether Test and Trace could have worked well enough to bring R below 1 and therefore stop the epidemic, but it is pretty clear that the system was a very expensive failure — even when backed up with stiff fines. Claims that it might be working better now are of limited interest given that vaccines will now surely do the heavy lifting in bringing Covid 19 under control.