Operation Moonshot ignored screening experts. No wonder it's failing
All eyes are fixed on vaccines, waiting and yearning, but when immunisation arrives, testing and tracing will long remain essential to keeping the virus suppressed due to the staggered rollout of the programme or resistance to uptake. But how you test is critical. It needs to draw on a deep well of experience – not a novel approach with the potential to waste of colossal sums of public money.
Sir Muir Grey, a screening expert writing in the BMJ – alongside Mike Gill, a former regional director of public health, England – has just delivered a devastating verdict on the effectiveness of the testing programme now being trialled in Liverpool, with mega-labs opening next year.
Needless to say Grey has not been consulted, despite being the author of the standard text on screening, and founder of the National Screening Committee in 1996, which put right a chaotic cervical screening programme. I was on that committee for several years, as he forged the criteria for what makes an effective screening project, what conditions and what protocols.
He is shocked to find this vast screening of the entire population for Covid-19 has not even been put before the committee. He writes, “If judged against the criteria drawn up by the UK’s National Screening Committee for appraisal of a programme’s viability, effectiveness, and appropriateness, it does not do well and has been already roundly criticised.” Interpret that as “very badly indeed” on every measure by which screening plans are normally assessed.
I learned from him on the committee, and he reminds me now, that when proposals for screening are put forward: “All screening programmes cause some harm with false positives and false negatives, some do more good than harm – and some do more good than harm at reasonable cost.” That should have been weighed in the balance before mass Covid screening, which he finds fails.
The Innova test, one of two in use in Liverpool, has not been evaluated in these conditions. Grey writes, “The test’s instructions for use state that it should not be used on asymptomatic people”, in other words, not for broad population screening. An evaluation by Porton Down and Oxford University suggests, “the test misses between one in two and one in four cases. The false positive rate of 0.6% means that at the current prevalence in Liverpool, for every person found truly positive, at least one other may be wrongly required to self-isolate.”
When infection is detected, “few currently adhere to self-isolation”, 20% being one estimate. Grey notes with his usual dry understatement that “this is an obvious area for improvement before we embark on an expensive screening programme”. What’s more, those on low incomes may be less likely to present for screening for fear of needing to self-isolate. That underlines, he writes, “the importance of reducing the rate of false positive results and providing appropriate support – financial, psychological and material – to people who must isolate.”
As the TUC, Labour and many other critics noted long ago, those on lowest incomes, most at risk, can least afford to take time off work, defeating the whole endeavour. Grey suggests to me when I called him this week that everyone should get at least the same as jury service: £65 a day. In Germany everyone is recompensed for their full pay. Why waste £100bn without this blindingly obvious necessity?
Grey reveals, astonishingly, that “there is no protocol for this pilot in the public domain, let alone systems specification or ethical approval”. Spending this monumental sum “on an unevaluated, under-designed national programme leading to a regressive, insufficiently supported intervention – in many cases of the wrong people – cannot be defended”. But perhaps, I ask him, in this crisis, there was no time? He says the National Screening Committee could have scrutinised it, setting the right objectives, “in a week or so”.
There are firm rules in screening. “You never get 100% participation” – but if done correctly, “80-90% is achievable”. Getting the last 5% can cost as much as reaching the first 90% – but, he points out, in this case the hardest to reach are the ones you most need.
In my time on the committee, preventing bad screening was often the key task. Schemes that looked brilliant at first sight may turn out to be brainless. Grey recalls the neurosurgeons who said screening could prevent strokes if all middle-aged people with an atypical headache were sent to be checked: the numbers would have been unmanageable. There was frequent pressure for prostate screening with PSA tests: men’s groups said it was unfair women had so much spent on breast cancer. But it would have led to needless surgery, with risk of incontinence and impotence for many men who would have died of something else long before prostate cancer developed. Antenatal ultrasound at first noted any small irregularity without knowing its significance: the result was too many women sent for amniocentesis, with a 1% miscarriage rate, so clearer ultrasound verdicts were imposed. Early breast cancer screening picked up every micro-calcification, which might never become a cancer, for excision. Bad screening programmes can cause fear and damage.
Grey calls for “an immediate pause” to this mass Covid screening of the symptomless, until it’s scrutinised by the National Screening Committee. A negative test may wrongly feel like a route to freedom, but that’s “premature”, he warns, without improving “the woeful performance of the ‘ find, test, trace and isolate’ system”. Focus first on those with symptoms among those groups most at risk, with good compensation for those told to isolate.
This gigantic screening plan bears